Journal of Environmental Sciences
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2023
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IF 6.9
Xingyu Liu,Jingkun Chen,Bowen Han,Renna Li,Le Shi,Zhongbiao Wu,Xiaole Weng
Zeolites are a promising support for Pd catalysts in lean methane (CH 4 ) combustion. Herein, three types of zeolites (H-MOR, H-ZSM-5 and H-Y) were selected to estimate their structural effects and deactivation mechanisms in CH 4 combustion. We show that variations in zeolite structure and surface acidity led to distinct changes in Pd states. Pd/H-MOR with external high-dispersing Pd nanoparticles exhibited the best apparent activity, with activation energy ( E a ) at 73 kJ/mol, while Pd/H-ZSM-5 displayed the highest turnover frequency (TOF) at 19.6 × 10 −3 s −1 , presumably owing to its large particles with more step sites providing active sites in one particle for CH 4 activation. Pd/H-Y with dispersed PdO within pore channels and/or Pd 2+ ions on ion-exchange sites yielded the lowest apparent activity and TOF. Furthermore, Pd/H-MOR and Pd/H-ZSM-5 were both stable under a dry condition, but introducing 3 vol.% H 2 O caused the CH 4 conversion rate on Pd/H-MOR drop from 100% to 63% and that on Pd/H-ZSM-5 decreased remarkably from 82% to 36%. The former was shown to originate from zeolite structural dealumination, and the latter principally owed to Pd aggregation and the loss of active PdO.
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Journal of Energy Chemistry
·
2023
·
IF 13.1
Jiaqian Ding,Xian Jiang,Caikang Wang,Zhuoya Zhu,Chang Xu,Yi Zhou,Xuan Wang,Qicheng Liu,Zhenyuan Liu,Yawen Tang,Jun Lin,Gengtao Fu
Ru with Pt-like hydrogen bond strength, knockdown cost (∼1/3 of Pt), and eximious stability is a competitive replacement for Pt-based catalysts towards the hydrogen evolution reaction (HER) in water splitting. The design of Ru-based catalysts via interface construction, crystal phase control, and specific light element doping to realize the impressive promotion of limited activity and stability remains challenging. Herein, we report the fabrication of Pd@RuP core-shell nanorods (NRs) via an epitaxial growth method, where ultrathin RuP shells extend the face-centered cubic ( fcc ) crystal structure and (111) plane of the Pd NRs core. Density functional theory results confirm that the core-shell interface engineering and P doping synergistically accelerate electron transfer and moderate the d -band center to generate a suitable affinity for H*, thus optimizing HER kinetics. Compared with Pd@Ru NRs and Pt/C, the Pd@RuP NRs exhibit preferable electrocatalytic stability and superior activity with a low overpotential of 18 mV at 10 mA cm −2 in the alkaline HER process. Furthermore, the integrated Pd@RuP//RuO 2 -based electrolyzer also displays a low operation potential of 1.42 V to acquire 10 mA cm −2 , demonstrating great potential for practical water electrolysis. Our work presents an efficient avenue to design Ru-based electrocatalysts via epitaxial growth for extraordinary HER performance.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
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IF 8.6
Jianhui Xu,Xin Fu,Yufeng Liu,Yunfei Zhang,Shenggui Chen,Dan Li,Chunhui Zhang,Jiale Gao,Yibo Fu
Electrocatalytic hydrodechlorination technology provides an attractive strategy to effectively eliminate the biotoxicity of halogenated organic pollutants (HOPs). Herein, we demonstrated a highly dispersed Pd loaded on blue TiO 2 nanotube arrays (Pd x -BTNA) cathode that can achieve efficient dechlorination and detoxification toward florfenicol (FLO). Characterization results indicated that strong interaction between Pd and BTNA was achieved through Pd-O bonds, which facilitated the electron transfer rate. Pd x -BTNA significantly outperformed other cathodes (i.e., BTNA, Pd x -TNA and Pd x -Ti) in the electrocatalytic dechlorination of FLO due to enhanced utilization of active H*. The dechlorination performances of FLO well followed the pseudo-first-order kinetic, and the reaction constant rate on Pd x -BTNA cathode (0.035 min −1 ) was 17.5, 1.94, 7.0 times higher than that on BTNA, Pd x -TNA and Pd x -Ti cathodes, respectively. Quenching experiments and electrochemical characterization indicated that both direct electron transfer and indirect reduction process mediated by H* were involved in the dechlorination of FLO. The optimal dechlorination efficiency of 98.79% was obtained by Pd x -BTNA cathode within 120 min at 1 mM PdCl 2 , applied cathode potential of −1.2 V. In addition, Pd x -BTNA exhibited superior stability and durability with almost no Pd leaching (0.0011 mg/L) during five dechlorination cycles. Our research proposed a novel strategy to design low noble Pd-loaded cathode material for efficient dechlorination and detoxification of HOPs.
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RSC Advances
·
2023
·Vol. 13
·期 35
·24628-24638
·
IF 3.9
Ji-qiu Zhang,Yu-Hao Wang,Shu-jing Zhang,Yang-qian Lin,Qing-qing Guan,Xi-meng Xu
Acetylene hydrogenation is a well-accepted solution to reduce by-products in the ethylene production process, while one of the key technical difficulties lies in developing a catalyst that can provide highly dispersed active sites. In this work, a highly crystalline layered covalent organic framework (COF) material (TbBpy) with excellent thermal stability was synthesized and firstly applied as support for ultrasmall Pd nanoparticles to catalyze acetylene hydrogenation. 100% of C2H2 conversion and 88.2% of C2H4 selectivity can be obtained at 120 °C with the space velocity of 70 000 h−1. The reaction mechanism was elucidated by applying a series of characterization techniques and theoretical calculation. The results indicate that the coordination between Pd and N atom in the bipyridine functional groups of COFs successfully increased the dispersibility and stability of Pd particles, and the introduction of COFs not only improved the adsorption of acetylene and H2 onto catalyst surface, but enhanced the electron transfer process, which can be responsible for the high selectivity and activity of catalyst. This work, for the first time, reported the excellent performance of Pd@TbBpy as a catalyst for acetylene hydrogenation and will facilitate the development and application of COFs materials in the area of petrochemicals.
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CATALYSIS LETTERS
·
2023
·Vol. 153
·期 10
·3044-3052
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IF 2.8
Li Kaihui,Xu Junyuan,Zhang Huan,Zhu Lihua
Abstract Cyclohexanone is a crucial intermediate for producing nylon and other industrial products. However, the direct hydrogenation of phenol for synthesizing cyclohexanone easily generates cyclohexanol and thus reduce the yield. In this work, the Pd/WO 3 catalysts with different Pd contents (Pd/WO 3 -1–0.21 wt%, Pd/WO 3 -2–0.69 wt%, Pd/WO 3 -3–2.20 wt%) are prepared via using sodium borohydride liquid phase reduction, which have good catalytic performance for phenol selective hydrogenation. The Pd/WO 3 -2 catalyst can achieve 92.9% conversion, 84.4% selectivity and high TOF (turnover frequency) of 349.1 h −1 under the reaction conditions (120 °C, 2 h, 3.0 MPa H 2 ). The nanostructures of the catalysts are extensively characterized by XRD, XPS, SEM, TEM, HRTEM, STEM and STEM-EDS elemental mapping and line-scanning. It is found that the Pd/WO 3 -2 catalyst has a high Pd dispersion and quite tiny Pd clusters. Alternatively, the stability experiment of Pd/WO 3 -2 indicates that the conversion decreases from 92.9% to 87.5% and the selectivity to cyclohexanone does not change significantly (84%) after it is recycled for five times. Graphic Abstract
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Jianguo Yu,Zehui Yu,Yunling Jia,Ting Ran,Ming Song,Yanshuang Zhang,Qing Wang,Yuning Qu,Lili Wang
Direct alcohol fuel cells' performance is significantly affected by the phase and composition of the catalyst, thereby the development of high-performance alcohol oxidation catalysts is essential. In this study, PVA preparation was used for the first time to create PdCu core-shell nanoflowers with a high electrochemically active surface area and a potent synergistic effect. Notably, the presence of PVA causes Pd and Cu nanoparticles with different reduction rates to form a core-shell structure, and the Pd nanoparticles continue to migrate regularly under the action of PVA, forming a flower-like morphology with a high degree of branching. Cu@Pd 22.3 catalyst exhibited 13 times higher catalytic performance (4353.04 mA mg Pd −1 ) than Pd/C (334.09 mA mg Pd −1 ) in ethylene glycol oxidation reaction. The Cu@Pd 22.3 catalyst also exhibits higher stability than commercial Pd/C in stability tests lasting up to 20,000 s. This core-shell combination and highly branched structural design result in more active sites for fast ion adsorption/desorption,offering an original method to improving the activity and endurance of polyol oxidation.
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Nano Research
·
2023
·
IF 9.9
Ye Zichen,Li Yun,Li Jingchao,Hu Xinyan,Zheng Jinyang,Zhang Gongxin,Xiang Sijin,Zhu Tianbao,Guo Zhide,Chen Xiaolan
Lactic acid (LA) plays a major role in the occurrence, development, and spread of cancer. Enlightened by its high accumulation in tumor site, a novel lactate oxidase (LOD) conjugated two-dimensional Pd@Ir nanoplatform (Pd@Ir-LOD, PIL) was fabricated to combine cascade reaction with photothermal for tumor therapy. In detail, the overexpressed LA in tumor microenvironment (TME) was a key factor to activate the PIL-based cascade reaction: (1) Plenty of H 2 O 2 could be generated from LA by the catalysis of LOD with O 2 ; (2) potent OH was produced from H 2 O 2 due to the peroxidase (POD)-like activity of PIL; (3) meantime, PIL’s catalase (CAT)-like activity could decompose part H 2 O 2 into O 2 to achieve the purpose of LA cyclic oxidization. Moreover, the reduced glutathione (GSH) scavenging capability of PIL might protect the produced reactive oxygen species (ROS) from being cleared to further improve the cascade therapeutic effect. More importantly, PIL had excellent photothermal conversion efficiency (37.35%) and manifested a surprising temperature rising effect in tumor. Taken together, the decreasing LA concentration, accumulation of high-toxic ROS, the depletion of GSH together with the higher intra-tumoral temperature potently enhanced in vivo antitumor therapy. Therefore, a promising therapeutic tactic based on PIL integrating endogenous LA consumption, chemodynamic therapy (CDT), and photothermal therapy (PTT) has been put forward.
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Di Wang,Hongcen Yang,Shuhao Tian,Guo Liu,Ying Wang,Xiao Sun,Zhixia Wang,Juan Hou,Fei Ma,Shanglong Peng
Hydrogen energy is regarded as the clean energy alternative for fossil energy. Hydrogen evolution reaction (HER) is a sustainable way for the production of hydrogen energy. However, commercial platinum (Pt) catalysts for HER are expensive and scarce, which will not fully meet the demand of the future market. Therefore, scientists have been actively exploring alternatives to Pt-based catalysts. Studies have shown that palladium (Pd) and Pt have similar catalytic activity in HER. Small molecular Pd nanoclusters can be used as a perfect HER activity center. Herein, anchoring of Pd nanoclusters (Pd NCs) on sulfur-vacancy-enriched ZnIn 2 S 4 nanosheets (Pd/ZIS-T) has been successfully achieved. The zeta potential value for ZnIn 2 S 4 is −59.9 mV, indicating that the surface of ZnIn 2 S 4 is abundant negatively charged in deionized water, thus providing plentiful anchoring sites to absorb Pd 2+ . The results show that the synergistic effect of Pd NCs and sulfur vacancies will endow the obtained catalyst with excellent electrocatalytic activity and stability. It also managed to reducing costs by reducing noble metal content. In particular, the Pd/ZIS-T electrocatalyst with excellent performance delivered low overpotential of 25 mV at 10 mA cm −2 and small Tafel slope of 33 mV dec -1 in acidic electrolyte.
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ChemCatChem
·
2023
·Vol. 15
·期 20
·e202300793
·
IF 4.5
Guoqing Wang,Miao Jiang,Zhao Sun,Leilei Qian,Guangjun Ji,Lei Ma,Cunyao Li,Hong Du,Li Yan,Yunjie Ding
Graphical A multifunctional heterogeneous Pd-POPs-CF 3 SO 3 H catalyst containing integrated acid and metal sites and anions was synthesized for tandem conversion of fructose to bio-diketones in good yield with an extraordinary TOF. Tandem conversion of biomass to value-added fine chemicals is a significant challenge. For instance, the production of fine chemicals from fructose involves conversion to 5-hydroxymethylfurfural (5-HMF), followed by another reaction and purification. Dual catalyst systems have been used in nearly every study on the tandem conversion of fructose to bio-diketones. Therefore, a sole multifunctional heterogeneous catalyst was developed in this study for the tandem conversion of fructose to bio-diketones, which has not been reported previously. Instrument corrosion and the separation or purification of 5-HMF were avoided using the multifunctional heterogeneous catalyst, which contained integrated active sites of acid, metal, and anions. The multifunctional CF 3 SO 3 H-functionalized porous-organic-polymers(POPs)-supported Pd catalyst (Pd-POPs-CF 3 SO 3 H) was prepared using a series of modifications. A bio-diketone yield of 51.0 % was achieved using Pd-POPs-CF 3 SO 3 H in the tandem conversion of fructose with an excellent TOF of 88.3 h −1 which is much more efficient than catalyst reported in literatures. Pd-POPs-CF 3 SO 3 H could be reused at least three times with stable performance. Control experiments and characterization results proved that the high specific surface area, hierarchical pore structure, abundance of CF 3 SO 3 −1 anions, and proximity of Pd moieties and acid sites (“The closer the better” principle) led to the decent performance for bio-diketone.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Xiulan Weng,Huijing Ma,Gary Owens,Zuliang Chen
Recently, bimetallic Fe-Pd nanoparticles were integrated with metal organic frameworks (MOFs) to produce a new composite catalyst with significant potential for organic contaminant removal due to enhanced adsorption and reduction. Here, 85.9 % of 2,4-dichlorophenol (2,4-DCP) was successfully removed from aqueous solution within 120 min when using a zinc-based zeolitic imidazolate framework (ZIF-8) embedded with Fe-Pd (Fe-Pd@ZIF-8). In comparison only 77.4 and 48.3 % was removed when using ZIF-8 or Fe-Pd alone. Thus, to better understand the function of composite components (ZIF-8 and Fe-Pd) in the removal of 2,4-DCP, and the specific removal mechanism involved, Fe-Pd@ZIF-8 was characterized before and after exposure to 2,4-DCP. This comparison revealed that 2,4-DCP was adsorbed onto the surface of the composite during exposure. Moreover, while ZIF-8 maintained stability following the removal of 2,4-DCP, Fe 0 was partially oxidized and Pd functioned as a catalyst in the removal process. Furthermore, kinetic studies demonstrated that the initial adsorption of 2,4-DCP conformed to a pseudo-second-order model and the subsequent reduction conformed to a pseudo-first-order model, whereas isothermal adsorption best fit the Freundlich adsorption model. This observation suggested that removal mechanism of 2,4-DCP involved both adsorption and dechlorination. Finally, Fe-Pd@ZIF-8 was applied to practically remove 2,4-DCP from wastewater, showing a 74.4 % removal efficiency which indicated that the composite was a potential new nanomaterial for practically removing organic contaminants from wastewater.
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FUEL
·
2022
·
IF 8.035
Defu Yin,Renjie Ji,Fanglin Lv,Long Jiang,Jingyun Zhang,Mingya Liu,Zhen Jia,Shitao Yu,Ruiyang Zhao,Yue Liu
Efficient catalysts are still the key to practical industrial applications. In this work, Pd-based catalyst was modified by doping metal Co to obtain Pd-Co@mSiO 2 bimetallic core–shell catalyst. The modified bimetallic core–shell catalyst was used in the hydrogenation of phenol, and the catalytic results showed that the Co modification effectively improved the catalytic performance of the Pd-based catalyst, especially, it reduced the activation energy of the reaction and greatly improve the conversion of phenol. Combined with characterization, it was found that Co doping reduced the particle size of Pd metal particles and affected the adsorption capacity of substrate phenol on the surface of Pd metal. The conversion of phenol was close to 99.9 % within 1 h at 80 °C, while the selectivity of cyclohexanone reached 95.4 %. In addition, the core–shell structure provided a stable environment for the catalyst, which still maintained high activity after being recycled for 5 times.
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Frontiers in Chemistry
·
2022
·
IF 5.545
Li Yongfeng,Liao Qianyan,Ling Weizhao,Ye Fan,Liu Fangfang,Zhang Xipeng,He Jiajun,Cheng Gao
Exploring high-efficiency and stable monolithic structured catalysts is vital for catalytic combustion of volatile organic compounds. Herein, we prepared a series of Pd/δ-MnO2 nanoflower arrays monolithic integrated catalysts (0.01–0.07 wt% theoretical Pd loading) via the hydrothermal growth of δ-MnO2 nanoflowers onto the honeycomb cordierite, which subsequently served as the carrier for loading the Pd nanoparticles (NPs) through the electroless plating route. Moreover, we characterized the resulting monolithic integrated catalysts in detail and evaluated their catalytic activities for toluene combustion, in comparison to the controlled samples including only Pd NPs loading and the δ-MnO2 nanoflower arrays. Amongst all the monolithic samples, the Pd/δ-MnO2 nanoflower arrays monolithic catalyst with 0.05 wt% theoretical Pd loading delivered the best catalytic performance, reaching 90% toluene conversion at 221°C at a gas hourly space velocity (GHSV) of 10,000 h−1. Moreover, this sample displayed superior catalytic activity for o-xylene combustion under a GHSV of 10,000 h−1. The monolithic sample with optimal catalytic activity also displayed excellent catalytic stability after 30 h constant reaction at 210 and 221°C.
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