DALTON TRANSACTIONS
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2021
·Vol. 50
·期 27
·9529-9539
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IF 4.39
Xin Guo,Lina Kong,Jianping Xu,Jing Chen,Lan Li
Surface decoration of noble-metal cocatalysts on graphitic phase carbon nitride (g-C3N4) with high efficiency and trace content for water splitting is exciting but difficult to achieve. Herein, we report the anchoring of Au and metallic/oxidized Pt nanoparticles (NPs) on g-C3N4 as cocatalysts via a photoreduction process for enhancing photocatalytic H2 production. Au NPs are preferentially decorated on g-C3N4, which can control the formation of metallic/oxidized Pt complex species. The well dispersed Au and metallic/oxidized Pt NPs improved the light-harvesting and the photo-generated carrier separation of g-C3N4. G-C3N4 sequentially decorated with Au (0.3 wt%) and metallic/oxidized Pt (0.3 wt%) cocatalysts, exhibited the highest and stable H2 evolution rates of 2560 and 139 μmol h−1 g−1 under simulated sunlight and visible light (λ ≥ 420 nm) irradiation, respectively, compared to the samples that are simultaneously and sequentially decorated with the same content of Pt and Au on g-C3N4. The enhanced photocatalytic activity is attributed to the synergistic effect of Au and metallic/oxidized Pt cocatalysts, i.e., the effective localized surface plasma resonance coupling between Pt and Au NPs, as well as electron-sink function of metallic Pt, which promote the generation and transfer of more carriers from g-C3N4 to the Pt species, in addition to the superior hydrogen evolution capacity of metallic and oxidized Pt. This work maximizes the performance of noble-metal cocatalysts with minimized content and provides the possibility of realizing efficient solar-to-fuel conversion.
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PubMed
高影响因子
FUEL
·
2020
·
IF 5.578
Muhammad Irfan,Aimin Li,Lei Zhang,Guozhao Ji,Yuan Gao
Catalytic gasification, coupled with in-situ CO 2 capture over Ni-CaO catalyst, is considered to be an effective approach for H 2 -rich and tar-free syngas production. However, the poor stability of Ni-CaO based catalyst raises a question regarding its large scale application. In this study, HfO 2 was used as a stabilizer and promoter for the Ni-CaO catalyst system. The stability of catalyst was evaluated through cyclic carbonation-calcination test with a thermogravimetric analyzer. The results showed that HfO 2 incorporated catalysts performed better stability towards cyclic CO 2 capture. The effect of different HfO 2 additions in catalyst, catalyst to municipal solid waste (C/MSW) ratio, gasification temperature, and moisture content (MC) of MSW was investigated on syngas composition, H 2 yield, dry gas yield (DGY) and product distribution (syngas, tar and char). The results indicated that H 2 yield was improved from 212 mL/g (without catalyst) to 442 mL/g with Ni-CaO (NC) catalyst and further improved with the application of HfO 2 promoted catalysts (Ni-CaO-HfO 2 ). The catalyst with 20% HfO 2 (NCH-20) exhibited maximum H 2 yield of 597 mL/g. Moreover, a significant reduction in tar content from 8.79 wt% (without catalyst), 3.19 wt% (with Ni-CaO) to 2.81 wt% (with NCH-20) was also recorded with HfO 2 promoted catalysts.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
·
IF 4.939
Xiaoming Liu,Xueya Chen,Luping Xu,Binquan Wu,Xinman Tu,Xubiao Luo,Fang Yang,Jun Lin
A series of non-noble metal ultrathin MoS 2 nanosheets modified Mn 0.2 Cd 0.8 S heterostructured composites were prepared by an ultrasonic assisted hydrothermal synthesis process. Comparing with the pristine Mn 0.2 Cd 0.8 S composite, the obtained ultrathin MoS 2 /Mn 0.2 Cd 0.8 S composites exhibited a significantly improved photocatalytic activity for hydrogen evolution from water with visible light response. The optimized photocatalytic activity toward MoS 2 /Mn 0.2 Cd 0.8 S composite is around 8 times of the pristine Mn 0.2 Cd 0.8 S composite. Moreover, the ultrathin MoS 2 /Mn 0.2 Cd 0.8 S composites displayed good photocatalytic stability in the course of photochemical reaction . The excellent photocatalytic activity of the ultrathin MoS 2 /Mn 0.2 Cd 0.8 S composites might be attributed to the formed heterojunctions in composites itself and the sufficient active edge sites in MoS 2 phase. A possible photocatalytic mechanism was tentatively proposed. Considering its excellent photocatalytic activity and good photochemical stability, the obtained ultrathin MoS 2 /Mn 0.2 Cd 0.8 S composite has potential application in photocatalytic hydrogen evolution from water by using solar energy.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Zhanbin Jin,Tingting Wei,Jiayu Huang,Fengyan Li,Yi Yang,Lin Xu
In this work, a novel direct Z-scheme g-C 3 N 5 /Zn 0.5 Cd 0.5 S (CN/ZCS) heterojunction was successfully synthesized. Furthermore, its photocatalytic activity for hydrogen production was also investigated, whose photoluminescence spectrum revealed the charge transfer procedure of g-C 3 N 5 and ZCS. Moreover, the optimized hydrogen production rate of ZCS with 15 wt% of g-C 3 N 5 (15% CN/ZCS) was about 142.8 mmol/h/g and quantum efficiency (Q.E.) was circa 33.7% under 420 nm monochromatic light. Compared with the pure ZCS and ZCS with 2 wt% of Pt, the 15% CN/ZCS composite exhibited considerable improved hydrogen production rate, which was about 20 times and 7 times, respectively. The formation of CN/ZCS composite resulted in faster separation of the photogenerated electron-hole pairs. Our work may supply valuable data for the application of g-C 3 N 5 on photocatalysis .
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ChemCatChem
·
2020
·Vol. 12
·期 21
·5504-5510
·
IF 4.853
Zi-Cheng Fu,Joshua T. Moore,Zi-Xin Yang,Jia-Jun Hu,Wen-Fu Fu
Graphical CoP for photocatalysis : Sphericalmesoporous SBA-15-supported CoP nanoparticlecatalysts tuning the highly efficient photocatalytic CO-and H 2 -generating pathways with product selectivity of up to 76.3 %and 99.9 % through switching solvent, respectively, were in situ fabricated by CoP embedded on the surface and interior of the porous s-SBA-15. The highly active spherical hybrid catalysts with diameters of 3–8 μm for robust selective CO 2 photoreduction and hydrogen production by switching solvent, CoP/(i)s-SBA-15 and CoP/(o)s-SBA-15, were in situ synthesized for the first time by incorporating CoP nanoparticles on the interior and outside of the spherical mesoporous Santa Barbara Amorphous (s-SBA)-type material s-SBA-15. CoP/(i)s-SBA-15 has a larger pore diameter of ∼9.5 nm, relative to ∼5.7 nm of CoP/(o)s-SBA-15, and a calculated Brunauer-Emmett-Teller surface area of ∼214 m 2 g −1 compared with ∼336 m 2 g −1 for the latter. In comparison with bare CoP, the composites exhibited excellent catalytic CO- and H 2 -generating performance with product selectivity of up to 76.3 % and 99.9 % through switching solvents containing Ru-based photosensitizer under ambient conditions, respectively. The influences of various solvents and electron donors, as well as the amounts of H 2 O, and catalyst on reaction kinetics for CO 2 reduction and H 2 production, and intrinsic properties of both catalysts were investigated and compared.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Kelin Hu,Feipeng Wang,Zijia Shen,Hongcheng Liu,Jianglin Xiong
In this paper, Pd/ZnO–SnO 2 hollow nanofibers prepared by electrospinning and magnetron sputtering . The sensing materials exhibited extraordinary hydrogen (H 2 ) sensing behavior – the response reached 171 at 270 °C, and besides, the response time and recovery time were as low as 19 s and less than 1 s at 240 °C, with steady high selectivity and good repeatability. Such an enhanced sensing performance could be attributed to the Pd/ZnO/SnO 2 ternary heterojunctions formed in the hollow nanofibers. Moreover, the materials were studied by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and especially the morphology formation process was further explained. The existence of Pd was confirmed to increase the resistance modulation range of heterojunction. In addition, the gas sensing mechanism based on the structure was proposed.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Xinwei Jiang,Qiang Liu,Chuchu Cheng,FangShu Xing,Cheng Chen,Caijin Huang
Developing a suitable and low-cost co-catalyst is highly desired for promoting photocatalytic water splitting of H 2 production. Herein, we adopted a simple in situ photodeposition strategy by coupling Mn 0.5 Cd 0.5 S with non-noble co-catalyst Ni 2 P to construct Ni 2 P/Mn 0.5 Cd 0.5 S composites and achieved obviously improved H 2 amount (31.83 mmol/h/g) in visible-light region, which is nearly 2.8 times than that of pure Mn 0.5 Cd 0.5 S. Such photocatalytic performance is in a relatively superior position among Mn x Cd 1−x S-based photocatalysts . The apparent quantum efficiency of Ni 2 P/Mn 0.5 Cd 0.5 S-7 composites reaches 32% at 420 nm. Through optical and photoelectrochemical measurements, a possible mechanism was proposed, it was found that the interface between metalloid Ni 2 P and Mn 0.5 Cd 0.5 S contacts closely, which facilitates transfer and separation of charge carriers, thus promotes the reduction of H + to H 2 . This study provides a new design of cut-price, high-efficiency photocatalyst for H 2 evolution.
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高影响因子
CARBON
·
2020
·
IF 8.821
Jinqiao Li,Xiaoteng Liu,Huinan Che,Chunbo Liu,Chunxiang Li
Realizing the efficient utilization of photogenerated carriers is a pivotal process to access the efficient transformation of light energy . Herein, we firstly practice a facile template method to synthesize O-doped crystalline/none-crystalline g-C 3 N 4 embedded nano-homojunction photocatalysts (CMCCN-x). This nano-homojunction makes the crystalline phase sufficiently contact with amorphous phase and further facilitates the photoinduced electron transformation. Therefore, the best performance catalyst CMCCN-5 well integrates the advantages of crystal g-C 3 N 4 and amorphous g-C 3 N 4 , which exhibits an excellent photogenerated carrier separation ability and abundant photocatalytic hydrogen evolution reaction activity sites. Excellent performance in the separation and use of photogenic carriers endows CMCCN-5 with efficient utilization of photogenerated carriers. Although there is a limited light absorption range (<460 nm), the photocatalytic hydrogen evolution rate of CMCCN-5 is up to 203.66 μmol h −1 under the visible light irradiation, about 86 times higher than pristine g-C 3 N 4 . The AQY numbers of CMCCN-5 at 420 nm and 450 nm are up to 26.9% and 14.0%, respectively. Thus, the significant effectiveness is forcefully proved for the facile construction of O-doped g-C 3 N 4 crystalline/none-crystalline nano-homojunction.
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Inorganic Chemistry Frontiers
·
2020
·Vol. 8
·期 5
·1154-1165
·
IF 5.958
Kunqiao Li,Wanbao Wu,Yanqiu Jiang,Zhe Wang,Xing Liu,Junzhuo Li,Debin Xia,Xianzhu Xu,Jizhuang Fan,Kaifeng Lin
The Z-scheme photocatalytic system has great potential in solar energy conservation with simultaneous wide light-absorption range, efficient electron–hole pair separation and strong redox ability. Herein, a direct Z-scheme g-C3N4/MoO3 photocatalytic composite with oxygen vacancies is successfully fabricated via a facile in situ method of a one-pot pyrolysis strategy. The as-prepared g-C3N4/MoO3 possesses a porous architecture with increased specific surface area. The existence of an oxygen vacancy in MoO3 is verified by XPS, UV-DRS analysis and electrochemical measurements. The g-C3N4/MoO3 exhibits superior visible-light photocatalytic performance for water splitting, as evidenced by an about 17-fold (20.52 μmol h−1) increase in the rate of H2 evolution relative to pristine C3N4 (1.23 μmol h−1). According to the characterization results and boosted photocatalytic performance, the migration and separation of photoinduced charge carriers in g-C3N4/MoO3 follows a possible mechanism based on a Z-scheme photocatalytic system constructed by the oxygen vacancies. The O-vacancy functions as the recombination and storage center for fast charge transfer through two components. The combined effect of defective MoO3 and a Z-scheme interfacial heterojunction has achieved greatly enhanced photocatalytic performance. This work demonstrates the facilitation effect of an effective Z-scheme system involving oxygen vacancies on the charge transfer to enhance the photocatalytic activity for water splitting.
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Nature Communications
·
2020
·Vol. 11
·期 1
·1-13
·
IF 12.121
Liu Yi,Zhang Jihua,Li Yapeng,Qian Qizhu,Li Ziyun,Zhu Yin,Zhang Genqiang
Replacing sluggish oxygen evolution reaction (OER) with hydrazine oxidation reaction (HzOR) to produce hydrogen has been considered as a more energy-efficient strategy than water splitting. However, the relatively high cell voltage in two-electrode system and the required external electric power hinder its scalable applications, especially in mobile devices. Herein, we report a bifunctional P, W co-doped Co 3 N nanowire array electrode with remarkable catalytic activity towards both HzOR (−55 mV at 10 mA cm −2 ) and hydrogen evolution reaction (HER, −41 mV at 10 mA cm −2 ). Inspiringly, a record low cell voltage of 28 mV is required to achieve 10 mA cm −2 in two-electrode system. DFT calculations decipher that the doping optimized H* adsorption/desorption and dehydrogenation kinetics could be the underlying mechanism. Importantly, a self-powered H 2 production system by integrating a direct hydrazine fuel cell with a hydrazine splitting electrolyzer can achieve a decent rate of 1.25 mmol h −1 at room temperature.
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PubMed
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Hong Du,Miao Jiang,Xiuyun Ma,Peifang Yan,Z. Conrad Zhang
The rapid consumption of fossil resources and the grim environmental situation encourage the application of renewable and clean energy resources. Conversion of biomass, which is a kind of renewable, CO 2 neutral as well as abundant reserves carbon containing resource, is significantly important. The production of fuels from biomass by means of gasification and Fischer-Tropsch synthesis is one of the most promising routes for industrial applications. The wax-free liquid fuels synthesis directly from H 2 -deficient syngas similar to bio-gas is highly advantageous for reducing investment and operating cost. Thus, the Mn-promoted meso-ZSM-5 supported cobalt catalyst was applied for the production of wax-free liquid fuels by catalytic H 2 -deficient syngas conversion in this study. The performance of the reaction was influenced obviously by Mn content. The cobalt dispersion increased with the addition of Mn, whereas the reduction degree decreased after Mn doping. Then, the balance between the dispersion and reduction degree led to the change in CO uptake followed a volcanic curve. The catalyst with moderate amount of Mn (1 wt%) had the suitable cobalt particle size and the maximum CO uptake. Thus, the highest CO conversion was obtained over Co-1Mn/meso-ZSM-5 catalyst thanks to its maximum exposed active sites. The appropriate amount of Mn addition also resulted in the decreasing of CH 4 selectivity. The highest space time yield of liquid fuels was acquired over the Co-1Mn/meso-ZSM-5 catalyst from H 2 -deficient syngas conversion under the moderate conditions.
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ChemCatChem
·
2020
·Vol. 12
·期 14
·3670-3678
·
IF 4.853
Mengjiao Zhang,Youwei Yang,Antai Li,Dawei Yao,Yueqi Gao,Busha Assaba Fayisa,Mei-Yan Wang,Shouying Huang,Jing Lv,Yue Wang,Xinbin Ma
Graphical Cu-based catalyst : In the hydrogenation of ethylene carbonate (EC), nanoflower-like catalysts with high fiber density exhibited nearly 98 % EC conversion when the H 2 /EC ratio was decreased to 60, while the catalyst with solid sphere structure required at least a H 2 /EC ratio of 140. This is attributed to the H 2 -enrichment effect of nanoflower-like morphology with dense fibers, which accelerated the reaction rate and achieved excellent activity at a low H 2 /EC ratio. The hydrogenation of ethylene carbonate (EC) to produce methanol and ethylene glycol (EG) is one of the key steps in the promising route for CO 2 utilization on a large scale. However, the high H 2 /EC ratio in feed (usually as 200∼300) is generally required to achieve favorable catalytic activity, inducing the high cost for H 2 circulation in the industrial application. Here, we report a series of nanoflower-like catalysts with curved fibers and open ends, among which the catalyst with the highest fiber density exhibited nearly 98 % EC conversion, 75 % methanol selectivity and over 99 % EG selectivity when the H 2 /EC ratio was decreased to 60. Combining the characterizations of active species distribution and high-pressure H 2 adsorption, it is demonstrated that the nanoflower-like morphology with dense fibers could remarkably enrich the hydrogen adsorption, consequently, accelerate the reaction rate and present an excellent performance at a low H 2 /EC ratio. These insights may provide instructive suggestions for further design of catalysts for the hydrogenation reactions.
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