Nature Communications
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2021
·Vol. 12
·期 1
·1-9
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IF 14.919
Zhang Lei,Chen Zhe,Liu Zhenpeng,Bu Jun,Ma Wenxiu,Yan Chen,Bai Rui,Lin Jin,Zhang Qiuyu,Liu Junzhi,Wang Tao,Zhang Jian
Electrocatalytic acetylene semihydrogenation is a promising alternative to thermocatalytic acetylene hydrogenation due to its environmental benignity and economic efficiency, but its performance is far below that of the thermocatalytic reaction because of strong competition from side reactions, including hydrogen evolution, overhydrogenation and carbon–carbon coupling reactions. We develop N–heterocyclic carbene–metal complexes, with electron–rich metal centers owing to the strongly σ–donating N–heterocyclic carbene ligands, as electrocatalysts for selective acetylene semihydrogenation. Experimental and theoretical investigations reveal that the copper sites in N–heterocyclic carbene–copper facilitate the absorption of electrophilic acetylene and the desorption of nucleophilic ethylene, ultimately suppressing the side reactions during electrocatalytic acetylene semihydrogenation, and exhibit superior semihydrogenation performance, with faradaic efficiencies of ≥98 % under pure acetylene flow. Even in a crude ethylene feed containing 1 % acetylene (1 × 10 4 ppm), N–heterocyclic carbene–copper affords a specific selectivity of >99 % during a 100–h stability test, continuous ethylene production with only ~30 ppm acetylene, a large space velocity of up to 9.6 × 10 5 mL·g cat −1 ·h −1 , and a turnover frequency of 2.1 × 10 −2 s −1 , dramatically outperforming currently reported thermocatalysts.
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CARBON
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2021
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IF 9.594
Yu Ma,Ding Chen,Dongdong Zhang,Hao Yu,Yapeng Zheng,Weijun Li,Lin Wang,Qiao Liu,Weiyou Yang
Freestanding air cathode catalyst with exceptional catalytic bifunctions for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly desirable for exploring rechargeable Zn–air batteries (ZABs) with low cost and high reliability. Here, a facile and scalable approach is demonstrated to prepare efficient and robust freestanding cathode catalyst that consists of dispersed Fe 3 C nanoparticles , rich Fe-N x /N-C species and carbon fibers networks with large specific surface area, which is based on one-pot in-situ coupling of Fe and N induced active sites within bacterial cellulose-derived carbon fibers networks. Its bifunctional activity parameter (Δ E ) for ORR and OER is 0.79 V, superior to those of single Fe- or N- modulated counterparts, and comparable to the state-of-the-art Pt/C + RuO 2 catalyst (0.79 V). This material can be directly used as freestanding and binder-free catalyst layer , and as-assembled ZABs exhibit a larger peak power density (173 mW cm −2 ), higher specific capacity (717 mA h g −1 , 10 mA cm −2 ) and better cycle stability (negligible activity decay after 165 h charge/discharge cycles) than those of Pt/C + RuO 2 -based devices, representing their potential applications in advanced energy conversion systems.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Xiaowen Liu,Yuanyuan Liu,Xin Zhang,Xiaodan Miao
In recent years, the development of low-cost and reusable green catalysts to reduce the organic pollutant of 4-nitrophenol (4-NP) into the utilizable intermediate of 4-aminophenol (4-AP) had attracted more and more attention. Herein, we reported a facile strategy to synthesize 3D N-doped graphene/bismuth (NGR/Bi) composites with efficient catalytic properties for 4-NP reduction. TGA exhibited NGR/8Bi catalyst came close to reach the maximum load of Bi (weight ratio 67%). NGR/8Bi catalyst had an apparent rate constant of 0.595 min −1 . After 8 min of catalytic reaction , the conversion of 4-NP reached 99.15%. Doped N facilitated the uniform distribution of Bi on graphene and improved the specific surface area and porosity of the catalyst, all of which contributed to the improvement of catalytic performance. The good reusability was attributed to that the microstructure of catalyst had not been changed significantly after used. The 3D network similar to aerogel made NGR/8Bi very easy to recycle and reuse. EPR spectra showed that H* active free radical was responsible for the conversion of 4-NP. This work revealed that the total surface area of metal particles in metal catalyst composites could affect catalytic performance essentially due to the surface plasma resonance effect.
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Frontiers in Bioengineering and Biotechnology
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2021
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IF 5.89
Lv Xianqing,Yang Guangxu,Gong Zhenggang,Cheng Xin,Shuai Li,Huang Liulian,Chen Lihui,Luo Xiaolin,Liu Jing
Chemical pretreatment followed by enzymatic hydrolysis has been regarded as a viable way to produce fermentable sugars. Phenylsulfonic acid (PSA) pretreatment could efficiently fractionate the non-cellulosic components (hemicelluloses and lignin) from bamboo and result in increased cellulose accessibility that was 10 times that of untreated bamboo. However, deposited lignin could trigger non-productive adsorption to enzymes, which therefore significantly decreased the enzymatic hydrolysis efficiency of PSA-pretreated bamboo substrates. Herein, poly(N-vinylcaprolactam) (PNVCL), a non-ionic surfactant, was developed as a novel additive for overcoming the non-productive adsorption of lignin during enzymatic hydrolysis. PNVCL was found to be not only more effective than those of commonly used lignosulfonate and polyvinyl alcohol for overcoming the negative effect of lignin, but also comparable to the robust Tween 20 and bovine serum albumin additives. A PNVCL loading at 1.2 g/L during enzymatic hydrolysis of PSA pretreated bamboo substrate could achieve an 80% cellulosic enzymatic conversion and meanwhile reduce the cellulase loading by three times as compared to that without additive. Mechanistic investigations indicated that PNVCL could block lignin residues through hydrophobic interactions and the resultant PNVCL coating resisted the adsorption of cellulase via electrostatic repulsion and/or hydration. This practical method can improve the lignocellulosic enzymatic hydrolysis efficiency and thereby increase the productivity and profitability of biorefinery.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2023
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IF 3.9
Zhe Zhao,Cheng Han,Xiaozhou Wang,Yingde Wang
Metallopolymers containing refractory metal in the main chain are highly desired but rarely reported as oxygen-free single-source precursors for preparing ultrahigh-temperature ceramics. Herein, a novel single-source precursor of poly-hafnium-borocarbosilane (PHBCNS) with an Hf–N–B backbone molecular structure was synthesized through the dehalogenation reaction between HfCl 4 and B(NHCH 3 ) 3 . The polymeric Hf–N–B chain with large bond angle and conjugated molecular structure endowed the PHBCNS precursor to be relatively stable, dissolvable, and meltable. Subsequent precursor pyrolysis up to 1800°C resulted in an HfC/HfB 2 nanocomposite comprising an Hf content of 87.54 wt%, with the average grain size of HfC and HfB2 to be 34.9 and 74.1 nm, respectively. The ceramization mechanism and phase evolution from the PHBCNS precursor to HfC/HfB 2 composite ceramics were thoroughly investigated. This work not only highlights a novel Hf–N–B backbone polymer with high metal content and good shaping properties but also provides fresh insights of designing single-source precursors for ultrahigh-temperature composite ceramics.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
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IF 4.2
Yuanchao Huang,Yuxi Si,Ying Xiang,Siyu Yao,Youwei Cheng
N-Ethylcarbazole (NEC), as a novel liquid organic hydrogen carrier (LOHC), has presented superiority to lower hydrogen storage cycle temperature and acceptable hydrogen storage capacity compared to benzene/toluene, etc. However, there is a lack of optimization of reaction conditions and cyclic testing for further commercial applications. Herein, we optimized the hydrogenation and dehydrogenation reaction conditions to obtain higher hydrogen storage capacity based on NEC/12H-NEC. The results revealed that 99.0% hydrogenation percentage and 91.7% dehydrogenation percentage could be available over Pd-based catalysts under optimal conditions. The cycling tests of the NEC-based hydrogenation and dehydrogenation reactions exhibited the desired stability after six cycles. Process simulation had been performed for the integration of NEC’s hydrogen storage unit in hydrogen vehicles, demonstrating that the actual hydrogen storage capacity of 5.3% and the energy output efficiency of 66% can be achieved. This work demonstrated the potential of the NEC/12H-NEC system for commercial applications.
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APPLIED CATALYSIS A-GENERAL
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2026
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IF 4.8
Yu Han,Yu-Wei Xiang,Zhi-Rong Fu,Xin Zhang,Jia-Yi Zhou,Xiang-Sen Wu,Yong Luo
The 8H-NEC was synthesized by different organic routes and used as the substrate for kinetic studies. • Ru/Al 2 O 3 catalysts with controllable Ru particle sizes were prepared. • Smaller Ru particles showed higher TOF and lower apparent activation energy. • Low-coordinated Ru line-edge sites enhanced 8H-NEC adsorption. N -ethylcarbazole (NEC) is a promising liquid organic hydrogen carrier (LOHC) for hydrogen storage, and Ru/Al 2 O 3 catalyst is one of the most widely used catalysts for NEC hydrogenation. However, previous studies have primarily focused on the chemical electronic effect of Ru/Al 2 O 3 catalyst, while neglecting the influence of geometric structure. In this work, Ru particle size effect on the rate-determining step of 8H- N -ethylcarbazole (8H-NEC) hydrogenation has been considered. Firstly, a series of Ru/Al 2 O 3 catalysts with controllable Ru particle sizes were prepared. After that, 8H-NEC was synthesized by different organic routes to serve as the substrate for catalytic and kinetic experiments. Results showed that as the Ru particle size increased from 1.4 to 5.3 nm, the turnover frequency (TOF) decreased from 59.7 to 32.2 min −1 and the apparent activation energy increased from 44.55 to 74.00 kJ·mol −1 . CO probe diffuse reflection infrared Fourier transform spectrum (CO-DRIFTS) and density functional theory (DFT) results demonstrated that superior catalytic performance of smaller Ru particles was associated with the exposure of more low-coordinated line-edge sites, which exhibited stronger adsorption toward 8H-NEC. This study offers new insights into the design of highly efficient catalysts of NEC hydrogenation. Download: Download high-res image (169KB) Download: Download full-size image
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CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Jierui Ye,Yuebing Gao,Qingtian Xu,Zhenfu Jin,Guomin Wu,Siqun Wang,Zengkun Cai,Ke Yang,Qiang Wu,Qian Li
Cellulose nanofibrils (CNFs) have widely attracted significant attention due to the excellent mechanical performance, biodegradability, and high surface functionality. However, the high flammability of CNFs commonly restricts their wider application. In this study, the intrinsically flame-resistant holocellulose nanofibrils (HCNFs, which is rich in both cellulose and hemicellulose) were obtained from bamboo under pretreatment using a highly efficient ternary deep eutectic solvent (TDES) and subsequential mechanical homogenization. The phytates and sulfate-containing HCNFs (PHCNFs) displayed nanofibril diameter of 3–5 nm and high aspect ratio of (∼500), and the aqueous suspension exhibited colloidal stability and high transmittance. The PHCNF films exhibited excellent fire resistance, mechanical and optical properties. Compared with raw HCNF, the limiting oxygen index (LOI) of PHCNF-120 film was up to 52.5 %, and the total heat release (THR) and peak heat release rate (PHRR) of PHCNF-120 films were significantly reduced by 92.2 % and 82.4 %, respectively. The flame retardant mechanism was attributed to the synergistic effect of P/N/S in both condensed phase and gaseous phases during the burning process. This work provides a novel, efficient strategy for developing eco-friendly flame-resistant and fireproof holocellulose-based nanomaterials.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2023
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IF 3.6
Mengxian Zhang,Xianrui Zhao,Junting Zhang,Zhigang Fang,Huan Xu,Hongtao Wang
TiB 2 reinforced Ti(C,N)-based cermet was produced by the reaction spark plasma sintering of Co, Ni, Ti, C, BN, Mo 2 C, WC, and TaC mixtures. To understand the mechanism of reaction sintering, systematic investigation on the microstructure evolution and displacement variation rule was carried out. In addition, the influence of C/BN molar ratio on the microstructures and performances of cermet was investigated. Except an initially increased pressure, three densification patterns were found. The first method was the Co Ti, Ti Ni, and Ti-BN diffusion reactions, resulting in a shrinkage of 22.06%. The second pattern was the viscous flow and dissolution-reprecipitation, which corresponded to the synthesis of Ti(C,N) and TiB 2 . In this process, the shrinkage ratio was increased by 35.62%. The final densification mainly originated from the viscous flow of metallic binder. It contributed to the transformation of macrovoids into microvoids, and an increased displacement of 30.10%. With the increasing of C/BN ratio, more C atoms diffused into Ti(C,N). Furthermore, core/rim structure-Ti(C,N) and coreless (W,Mo,Ta,Ti)(C,N) were fabricated. However, the microvoids in cermets enhanced. As a result, the hardness and fracture toughness first increased and then decreased. Results from this work are helpful to understand the reaction spark plasma sintering technique, and can enrich the preparation method of cermet.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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IF 22.1
Shiyan Li,Hongquan Fu,Xingshuai Zhang,Xu Liu,Giulia Tuci,Giuliano Giambastiani,Cuong Pham-Huu,Yuefeng Liu
H 2 S selective oxidation to elemental sulfur (S 8 ) is a typical reaction where the mass product diffusion ( e.g ., S 8 ) through the catalytic bed is crucial as well as the reagents accessibility ( e.g ., H 2 S, O 2 ) to the active sites. The NaNO 3 -assisted pyrolysis of polyacrylamide was applied to synthesize defect-enriched N-doped carbon nanosheets with thickness up to c.a. 2 nm, featured by fully accessible and highly interconnected pores, for boosting the H 2 S selective oxidation process. The PAM-0.3-700 sample has revealed an unprecedented desulfurization activity with sulfur formation rate of 1165 g sulfur kg cat. −1 h −1 , other than a remarkable stability (>80 h). Experimental and theoretical studies have unveiled the critical role of edge sites containing unpaired electrons and nitrogen species with respect to the material aptitude towards O 2 dissociation and HS - activation. The material in presence of a highly interconnected porous network facilitates the reactants/product diffusion especially for catalysis operated under harsh experimental conditions.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2023
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IF 9.9
Lixuan Zhang,Sibing Xie,Anqi Li,Yu Li,Fenghua Zheng,Youguo Huang,Qichang Pan,Qingyu Li,Hongqiang Wang
Metal sulfides have been considered promising anode materials for lithium-ion batteries (LIBs), due to their high capacity. However, the poor cycle stability induced by the sluggish kinetics and poor structural stability hampers their practical application in LIBs. In this work, MoS 2 /MnS/SnS trimetallic sulfides heterostructure coated with N -doped carbon nanorods (MMSS@NC) is designed through a simple method involving co-precipitation, metal chelate-assisted reaction, and in-situ sulfurization method. In such designed MMSS@NC, a synergetic effect of heterojunctions and carbon layer is simultaneously constructed, which can significantly improve ionic and electronic diffusion kinetics, as well as maintain the structural stability of MMSS@NC during the repeated lithiation/delithiation process. When applied as anode materials for LIBs, the MMSS@NC composite shows superior long-term cycle performance (1145.0 mAh/g after 1100 cycles at 1.0 A/g), as well as excellent rate performance (565.3 mAh/g at 5.0 A/g). This work provides a unique strategy for the construction of multiple metal sulfide anodes for high-performance LIBs.
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DIAMOND AND RELATED MATERIALS
·
2023
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IF 4.1
Huajun Zhou,Haifeng Cao,Yongping Qu,Yanzhong Wang
Molybdenum oxides are widely used as electrocatalysts due to their polymetallic oxidation state, abundant reactive sites and low production cost. However, the low electrical conductivity and easy agglomeration has limited their practical application. Here, MoO 3 nanowires encapsulated with ZIF-67 polyhedra were grown in situ on expanded graphite paper (EGP) by a simple hydrothermal synthesis method, and then the precursors were pyrolyzed to obtain self-supported Co-MoO x @N-doped carbon/EGP composites. Thanks to the three-dimensional porous structure and the synergistic effect of Co and multi-valance MoO x , the as-prepared Co-MoO x @N-doped carbon/EGP exhibits the excellent performances of OER (η 10 = 256 mV) and HER (η 10 = 138 mV), and a small Tafel slope and good durability. Furthermore, the assembled water splitting device achieved a current density of 10 mA cm −2 at a low voltage of 1.62 V and the excellent stability after 24 h continuous water splitting.
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