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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]

Advancing the development of economical, high-performance, and durable non-precious metal electrocatalysts for oxygen evolution reaction (OER) holds critical significance. This study presents a self-supporting ternary metal phosphide (NiCoFe–P/NF) electrode developed by direct phosphating metal-organic frameworks (MOFs) precursor. Benefiting from a three-dimensional hierarchical porous structure, optimized electronic configuration, high electrical conductivity, and synergistic effect of multiple elements, the synthesized NiCoFe–P/NF electrocatalyst exhibits exceptional catalytic performance compared to the monometallic or bimetallic phosphides, achieving a low overpotential of 209 mV and a Tafel slope of 29 mV dec−1 at 10 mA cm−2 in 1 M KOH solution. In addition, the prepared catalyst exhibits superior stability and durability, as evidenced by its well-preserved morphology after 48 h of stability test. Furthermore, at a high current density of 100 mA cm−2, the long-term efficiency remains >90% even after 96 h. Density functional theory (DFT) calculations reveal that the high catalytic performance of the NiCoFe–P/NF catalyst is ascribed to modified electronic states and lower adsorption energy to the related species. This study not only presents the synthesis of extremely stable and active OER catalysts but also offers a novel and practical method for the development of new catalysts. [Display omitted] • Self-supporting trimetallic phosphide was investigated for OER. • NiCoFe–P/NF electrode provides superior OER activity and stability. • DFT calculations explain the origin of the high catalytic activity. • A chemically uniform trimetallic two-dimensional MOF served as the precursor. [ABSTRACT FROM AUTHOR]

• Co 3 V 2 O 8 -T (T = temperature/°C) are prepared as bifunctional electrocatalysts. • Co 3 V 2 O 8 -400 nanofibers show small Tafel slopes of 43 and 63 mV dec−1 for ORR and OER. • The Co 3 V 2 O 8 -400 nanofiber has the best catalytic activities for ORR and OER. • The mechanism of Co 3 V 2 O 8 -400 nanofiber is simulated by DFT. Highly active and stable bifunctional electrocatalysts towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are necessary for practical fuel cells, metal-air batteries, and water splitting. Herein, we report a series of bifunctional Co 3 V 2 O 8 -T (T = temperature/°C) electrocatalysts by using Co-carbon electrospun nanofiber as a template, followed by a one-step calcination process. As expected, the developed Co 3 V 2 O 8 -400 nanofiber electrocatalyst shows a very small Tafel slope of 43 and 63 mV dec−1 for the ORR and OER in the alkaline solution, respectively. In addition, density functional theory (DFT) calculations reveal that the metallic conductivity and interface V-Co interaction of Co 3 V 2 O 8 -400 nanofiber boost ORR and OER electrocatalytic reactions. [ABSTRACT FROM AUTHOR]