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Self-driven recycling of sulfur-containing wastewater and hydrogen production is a novel concept that integrates environmental protection and new energy development. In this study, we designed for the first time a Zn-air battery self-driven coupling system for the hydrogen evolution reaction (HER), sulfur oxidation reaction (SOR) and developed a trifunctional catalyst suitable for this system capable of HER, SOR, and oxygen reduction reaction (ORR). By synthesizing cobalt sulfide (Co 3 S 4) in situ on nickel foam (NF), we obtained Co 3 S 4 /NF monolithic catalyst. It only requires 0.312 V and 0.244 V in SOR and HER, respectively, at 100 mA cm−2. Based on this achievement, the SOR||HER coupled electrolysis system was assembled, which achieved 0.69 V at 100 mA cm−2. Furthermore, the Zn-air battery (using Co 3 S 4 as ORR catalyst) could spontaneously drive the SOR||HER system to achieve high-rate hydrogen production. These findings provide promising opportunities for zero-energy consumption H 2 production and recycling of sulfur-containing wastewater. [Display omitted] • The self-driven SOR||HER hybrid electrolysis system was successfully designed. • Co 3 S 4 electrocatalysts were grown on Ni foam as three-dimensional catalyst for HER, SOR and ORR. • The electrolysis can be realized without energy consumption. • The sulfur-containing waste water can be recycled and H 2 generation occurs spontaneously. [ABSTRACT FROM AUTHOR]

To improve the stability of molybdenum carbide catalysts in dimethyl ether steam reforming (DSR), the inactivation mechanism and the performance of Pt modified catalyst has been investigated. The Mo 2 C oxidation induced by H 2 O is verified to be the main reason of catalytic deactivation. After modified with Pt, the H 2 production rate and selectivity are greatly enhanced, reaches 1605 μmol min−1·g cat −1 at 350 °C, in comparison to that of the Mo 2 C/Al 2 O 3 catalyst. Moreover, the 2%Pt–Mo 2 C/Al 2 O 3 catalyst is more stable with only 20% activity loss after 50 h on stream compares to the 73% activity loss in 12 h with Mo 2 C/Al 2 O 3 catalyst. By means of in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), the enhancement brought by Pt is ascribed to the consumption acceleration of intermediate oxygen species on catalyst surface and the decline of onset temperature of DSR reaction. It is expected that these findings can lead us to more practical molybdenum carbide catalysts in DSR. • Mo 2 C/Al 2 O 3 exhibits good activity in dimethyl ether steam reforming reaction. • The deactivation of molybdenum carbide is due to H 2 O oxidation. • Pt modification improves the stability by protecting Mo 2 C from surface oxidation. • Pt facilitates the formation of intermediates at lower temperatures. [ABSTRACT FROM AUTHOR]

Developing highly active catalyst for oxygen evolution reaction (OER) with low noble metal loading is crucial for the application of proton exchange membrane (PEM) water electrolysis. Ir-transition metal (TM) binary catalyst with chemical leaching was reported to perform excellent activity with TM leaching. However, most of the studies on the activation-decay focused on the final status, and the variation process remains unclear. With cysteamine·HCl, a modified facile molten salt method was applied to prepared highly active Ir–Ni mixed oxide (c-xNiIrMO), which perform 5.5 times higher mass activity than commercial IrO 2. The variation of active surface area, intrinsic activity, conductivity of prepared catalyst layer during the activation process are studied to unveil the key factors for the activity enhancement. With further stability test, c-xNiIrMO with Ni content lower than 67% performs decrease intrinsic activity and improved kinetic performance in the first hundred cycles. After obtaining a stable Ir 0.95 Ni 0.05 O x structure, further cycling results in typical activity decay with dissolution of Ir. • Cysteamine·HCl modified c-NiIrMO performs a highest 2.51 times of Ir mass activity compared to nc-NiIrMO. • Cysteamine·HCl not only plays a role in particle fining but also contributes to the formation of active Ir–OH. • For activation with Ni leaching, surface enlargement plays a key role for c-IrNiMO with Ni content lower than 40%. • Formation of Ir–OH is the dominant factor for the activation of sample with higher Ni content. • A three–step variation process dominated by Ni and Ir dissolution can be observed in the activation-decay process. [ABSTRACT FROM AUTHOR]

A new one-step method for synthesize cuprous oxide nanosphere without any additive surfactant in room temperature and atmospheric pressure was carried. The nanospheres with the diameters less than 100 nm were well-dispersed and formed the core–shell structure with the GO. The partial reduction of GO increases the atomic percentage of sp 2 carbon (graphene sheets). It was found that sp 2 carbon with better conductivity plays an important role in mitigating electron–hole recombination and enhancing electron transfer between Cu 2 O and GO and thus enhance the photocatalytic activity. The highest hydrogen yields for GO-modified samples (118.3 μmol) were more than twice as large as that of bare Cu 2 O nanosphere (44.6 μmol). [ABSTRACT FROM AUTHOR]

Experimental and computational (DFT) approaches were carried out to investigate oxygen vacancies on cerium dioxide. Computational result indicates oxygen vacancies can shorten the band gap of CeO 2 and enhance the absorption for visible light because Ce (III) created by generation of oxygen vacancies is easier for excitation than Ce (IV) under same irradiation. The order of calculated band gap for Ce 16 O 31 , (111) < (113) < (133), and the absorption data suggests that (111) plane may be the most ideal position for oxygen vacancies to enhance photocatalytic activity. The result has been tested and verified by experimental study, including UV–Vis spectra, XPS, XRD and PL. The enhanced hydrogen productions of CeO 2 samples, from 34.8 μmol to 63.0 μmol, are 2.0–3.5 times as high as that of commercial CeO 2 (17.8 μmol). [ABSTRACT FROM AUTHOR]

To enhance the heat and mass transfer during dimethyl ether (DME) steam reforming, a micro-reactor with catalyst coated on nickel foam support was designed and fabricated. A two-dimensional numerical model with SIMPLE algorithm and finite volume method was used to investigate 1) the fluid flow, 2) the heat transfer and 3) chemical reactions consist of DME hydrolysis, methanol steam reforming, methanol decomposition and water gas shift reactions. Both the numerical and the experimental results showed that the DME conversion in the micro-reactor is higher than that in the fixed bed reactor. The numerical study also showed that the velocity and the temperature distribution were more uniform in the micro-reactor. Wall temperature, porosity and steam/DME ratio have been investigated in order to optimize the process in the micro-reactor. The wall temperature of 270 °C and the steam/DME feed ratio of 5 were recommended. Meanwhile the results indicate that a larger porosity will give a higher DME conversion and CO concentration. [ABSTRACT FROM AUTHOR]

IrO 2 was electro-deposited on hydrogenated TiO 2 nanotube arrays (TNTA) to form IrO 2 /H-TNTA for oxygen evolution reaction (OER). Hydrogenation by calcining in H 2 atmosphere was conducted to improve the electric conductivity, which was owing to partially reduce of Ti 4+ in TNTA. It was found that hydrogenated TiO 2 can facilitate the electro-deposition of IrO 2 , and elevate the OER activity compared to that of non-calcined and air-calcined TNTA, which would be due to the improved conductivity of H-TNTA. IrO 2 /H-TNTA shows a five-fold higher activity than IrO 2 /air-TNTA with the same loading amount. The coverage of IrO 2 on the surface of hydrogenated TNTA is crucial to the stability of catalyst and with the increased loading amount of IrO 2 , IrO 2 /H-TNTA shows much higher stability. [ABSTRACT FROM AUTHOR]

A series of Ni-based catalysts supported on Ce–Zr–O were synthesized via impregnation and applied in the reverse water gas shift reaction (RWGS). BET, XRD, TPR, SEM, TEM and XPS were employed as the characterization of catalysts. Catalytic activities of Ni/Ce–Zr–O with different Ni contents were evaluated in RWGS under atmospheric pressure and at the temperature range of 550–750 °C in a fixed-bed quartz reactor. CO 2 conversion reaches 49.66% and maintains stable after 80 h of reaction over 3 wt% Ni/Ce–Zr–O. CO selectivity can reach 99.65% for the catalyst with 10 wt% Ni at 750 °C. The Ni/Ce–Zr–O catalyst provides high activity, stability and selectivity in the conversion of CO 2 to CO at high temperature. Ce–Zr–O solid solution is formed by co-precipitation and Ni is able to be incorporated into the Ce–Zr–O lattice via impregnation. The Ni species on catalyst surface can be considered as the active site for RWGS. [ABSTRACT FROM AUTHOR]

Abstract: Hydrogen production from catalytic steam reforming of model compound acetic acid of bio-oil was investigated under atmospheric pressure in a bench-scale fixed-bed reactor and a series of Ni catalysts supported on ceria–zirconia were prepared via co-precipitation with varying contents of Ni and Ce loading. Simultaneously, effects of reaction temperature, and molar ratio of steam to carbon fed, liquid hourly space velocity (LHSV) were also explored. The results indicated that the 12Ni/7.5Ce-Zr-O catalyst was superior to other catalysts with different Ni and Ce loading. At T = 650 °C, S/C = 3, LHSV = 2.8 h−1, the reaction over Ni catalyst supported on ceria–zirconia turns out that the highest activity and the maximum hydrogen selectivity of 83.4% and the minimum methane selectivity of 0.39% are attained. Besides, Ni catalyst supported on ceria–zirconia shows good stability during 25 h continuous reaction without any deactivation. [Copyright &y& Elsevier]