查看更多>>摘要：? 2022 Elsevier B.V.To design heterojunction electrocatalysts for water splitting in industrial plants, replacing RuO2, IrO2, and Pt/C remains challenging. We prepared heterostructures of nickel selenide (NiSe) and cobalt-iron layer double hydroxide (CoFe[sbnd]LDH), CoFe[sbnd]LDH@NiSe, using hydrothermal and electrodeposition processes. The interfacial coupling enhanced the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). The CoFe[sbnd]LDH@NiSe required an overpotential of 127 mV and 38 mV for a current density of 10 mA cm?2 with a Tafel slope of 37 mV dec?1 and 33 mV dec?1 for OER and HER in alkaline solutions. Density functional theory calculations showed the enhancement of OER performance. The catalytic activity of CoFe[sbnd]LDH@NiSe increased the electronic conductivity, enhancing the water splitting with 10 mA cm?2 at 1.51 V. The robustness was demonstrated by the long-term stability for 120 h. This study provides a strategy for developing heteronanostructure electrocatalysts for water splitting in fields such as metal-air batteries and energy storage.
查看更多>>摘要：? 2022 Elsevier B.V.The direct methane (CH4) oxidation to high value-added C1 chemicals is a great promising strategy to explore the CH4 resource utilization. However, the low activity and selectivity of catalytic performance remains a great conundrum due to the difficulty to activate the C[sbnd]H bond and the unmanageable over oxidation. Herein, PdxAuy nanowires (NWs) with various Pd/Au atomic ratios are presented as ideal models to explore the atomic-level effect of PdAu atoms for the direct CH4 oxidation. The influence of reaction parameters are systematically investigated, and Pd9Au1 NWs display a maximum yield of 2890.3 μmol g?1 h?1 with 99% selectivity for the liquid C1 oxygenated products. This enhanced performance is attributed to the combination of one-dimensional structure and the synergistic effect from the suitable portion of Au on Pd sites, which regulates bond strength between adsorbed radicals (?OH, ?OOH, ?CH3) and PdAu atoms, confirmed by the density function theory calculations.
查看更多>>摘要：? 2022 Elsevier B.V.The electrochemical N2 reduction reaction (NRR) is greatly challenged by relatively low faradaic efficiency (FE) owing to fierce competition from the H2 evolution reaction (HER) suffered by the current transition-metal electrocatalysts (d-block elements). Considering the unique electronic structure of group-VA pnictogens (p-block elements) that is complementary to d-block elements in HER suppression, we report a conceptually new Janus electrocatalyst to tackle the selectivity challenge. Specifically, an amorphous NiSb2O6–x nanofiber is synthesized, in which Ni and Sb contribute to a synergistic catalysis pathway for inhibiting the two-electron transfer process of HER as well as activating the adsorbed N2 molecules. Moreover, amorphization is able to produce more oxygen vacancies, thus mimicking the “π back-donation’’ process to promote the NRR performance. Benefiting from this coupled element design and amorphization strategy, the amorphous NiSb2O6–x nanofiber significantly outperforms either component (NiO or Sb2O4) as well as its crystalline counterparts in terms of NH3 yield and FE.
查看更多>>摘要：? 2022 Elsevier B.V.This study introduces how pulse-reverse electrodeposition (PRED) affects the properties of nickel phosphorus (NiP) films and improves the performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The impact of electrochemical parameters in PRED on HER and OER activities is explored, indicating that changes in two activities of PRED dissolution step are opposite. An increase in dissolution amount during PRED enhances OER while decreasing HER activity. The Mott-Schottky analysis reveals that improvement in HER by adopting PRED is due to an increase in the reactivity of active sites. On the contrary, OER is enhanced due to the number of active sites on the surface of NiP films increased by the excess dissolution during PRED. Surface analyses suggest that the opposite response of HER and OER is caused by different factors; uniform formation of NiP governs HER activity while removability of phosphate determines the exposure of OER-active Ni oxide phases.
查看更多>>摘要：? 2022 Elsevier B.V.Herein, CdS/ethanediamine (protonated) hybrid nanowires (CdS/EDA NW) three-dimensional (3D) network structure photocatalysts with tunable sulfur vacancy concentrations were fabricated. The protonated EDA molecules modified on the surafce of CdS to assemble into 3D structure with large specific surface area can not only effectively capture visible light, but also significantly enhance the separation and transportation of charge carriers. And EDA is also conducive to CO2 adsorption. Meanwhile, the rich sulfur vacancies (VS-R) on the surface of CdS/EDA NW can trap more photogenerated electrons to further prolong carries lifetime as well as effectively promote the hydrogen adsorption and CO2 activation. Hence, the VS-R mediated 3D CdS/EDA NW exhibits the high visible light photocatalytic syngas CO and H2 formation rate of 115.6 and 959.4 μmol g?1 h?1 (CO: H2 = 1: 8.3) respectively. This work provides a promising idea to design efficient catalysts through multiple collaborative strategies for syngas production via CO2 photoreduction.
查看更多>>摘要：? 2022 Elsevier B.V.Developing efficient electrocatalysts is of significance for hydrogen production in acid electrolyte. In this work, we report a facile decoration of ruthenium species onto tungsten oxides to construct the Mott-Schottky heterojunction electrocatalyst for hydrogen evolution. The resultant Ru-WO2.72 hybrid exhibits a superior Ru-based mass activity of 161.6 times higher than that of commercial Ru/C for hydrogen evolution, featuring a Tafel slope of 50 mV dec?1 and 40 mV overpotential at the current density of 10 mA cm?2. The uniform distribution of Ru species triggers a strong electron transfer across the Ru-WO2.72 Schottky barrier, resulting in a largely increased local electron density on the active Ru surface. Such electron enrichment induced by the Mott-Schottky effect at the metal-metal oxides interface is responsible for enhanced hydrogen production. This work demonstrates an effective strategy by Mott-Schottky effect to regulate electron distribution, which would evoke more inspiration in designing efficient electrocatalysis and beyond.
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