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Electrocatalytic O2 conversion and water-splitting hold great promise to enable the chemicals–electricity inter-transition in many renewable-energy initiatives. Enhancing the kinetics of the oxygen reduction reaction (ORR) is challenging. Here, we present that Zn3(VO4)2/Ni(OH)2/rGO (reduced graphene oxide) nanosheet arrays-a Zn3(VO4)2/Ni(OH)2 composite in the form of nanometre-thick nanosheets on an rGO substrate-serve as an efficient and stable electrocatalyst for the ORR in alkaline electrolytes. The thin-sheet structure and smaller free energy of Zn3(VO4)2/Ni(OH)2, as well as the excellent conductivity of the rGO substrate, enable a large electrochemically-active surface area and a high electron transport, contributing to the superior electrocatalytic oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Furthermore, Zn3(VO4)2/Ni(OH)2/rGO and Zn3(VO4)2/Ni(OH)2 samples exhibit remarkable long-term water-splitting stability of 48 h. Density functional theory (DFT) calculations reveal the optimized intermediate affinity ability at the Ni(OH)2 side, due to electrons transferring from Ni(OH)2 to Zn3(VO4)2. Additionally, the higher hybridization degree of density of states (DOS) boosts electron transfer in the electrocatalytic process. More broadly, this work provides new inspiration for the construction of a novel noble metal-free electrocatalyst that could show great promise in energy electrocatalysis. [ABSTRACT FROM AUTHOR]

Antimony (Sb) as a low-toxic and cost-effective metal is a promising material to catalyse CO 2 electroreduction to formate with practical viability. However, monometallic Sb suffers from intrinsically low catalytic activity and the competing hydrogen evolution. Here, we report nanoporous Sb-Bi alloys for substantially improving the catalytic activity of Sb and suppressing hydrogen evolution. The optimal Sb-Bi alloy exhibits a maximum Faradaic efficiency of 95.8 % toward formate production, surpassing the 11.6 % of monometallic Sb counterpart. Operating the catalyst in the flow cell demonstrates a formate partial current density of 734 mA cm−2 and cathodic energy efficiency of 59 % at a moderate overpotential of 800 mV, representing a record formate-production performance so far. Experimental and theoretical studies indicate that the Sb-Bi interactions activate Sb sites to selectively stabilize *OCHO intermediates, facilitating CO 2 -to-formate conversion. This work offers insights in manipulating bimetallic interactions to transform inert materials into active catalysts for efficient electrocatalysis. [Display omitted] • Sb-Bi interactions induce electrocatalytic switching from HER to CO 2 ER. • Sb 2 Bi 6 exhibits a maximum formate selectivity of 95.8 % in an H-type cell. • Sb 2 Bi 6 achieves a record formate activity of 734 mA cm−2 in a flow cell. • Sb-Bi interactions facilitate Sb sites to stabilize *OCHO for formate formation. [ABSTRACT FROM AUTHOR]