Developing low-cost, high performance, stable non-noble bifunctional electrocatalysts for overall water splitting is of great importance for future energy supplement. Despite recent advances in the synthesis of transition metal selenide nanostructures, the fabrication of porous nanosheet based binder-free electrode with more active sites remains a major challenge. Herein, the self-templating construction of a porous CoSe2 nanosheet array on carbon cloth (p-CoSe2/CC) has been reported by vapor selenizing the preprepared α-Co­(OH)2 nanosheet array precursor. Arising from large active surface area, fast diffusion of generated gas and strong structural stability, the as-obtained p-CoSe2/CC can serve as an efficient bifunctional electrocatalyst for both OER and HER in alkaline electrolyte, with a current density of 10 mA cm–2 at overpotential of 243 mV for OER and 138 mV for HER, respectively. Moreover, when p-CoSe2/CC is assembled as an alkaline electrolyzor, it only needs a cell voltage of 1.62 V at 10 mA cm–2 and shows excellent long-term stability of 20 h. The versatile fabrication strategy with self-templated porous structure proves a new way to construct other advanced metal selenide for energy conversion and storage.

Based on the in situ DRIFTS studies, the mechanism of formation and decomposition of NH4NO3 (decomposition to N2O) over Cu-SSZ-13 with different Cu loadings was investigated. Under standard SCR conditions, NH4NO2 can form over all catalysts, which can be more easily oxidized to NH4NO3 over higher Cu content catalysts because of their stronger oxidative ability resulting from the elevation of Cu­(OH)+. Hence, a higher Cu content leads to more low-temperature N2O formation, while N2O barely occurred over Cu-0 and Cu-0.7 catalysts. When NO2 exists, NO3 – forms from the disproportionation reaction of NO2 first, then reacts with NH3 to form NH4NO3, leading to N2O formation over all catalysts. Nevertheless, Cu2+ is active for the reaction between NH4NO3 and NO. The increase of Cu2+ allows more NH4NO3 consumption, and the self-inhibition of NH4NO3 alleviates, which allows NH4NO3 to decompose to N2O at lower temperatures, and N2O formation peak shifts toward lower temperatures.

Self-supported binary hybrid heterogeneous CoFe LDH/Co0.85Se nanosheet array catalyst for efficient oxygen evolution reaction.

An ultrathin carbon-coated CoO composite catalyst grown on carbon cloth was developed for efficient alkaline HER.

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