Constructing dual active sites for synergistic electrocatalysis of hydrogen oxidation: single-metal-atoms anchored on WC2O2 MXene

The promising alkaline exchange membrane fuel cells (AEMFCs) are subject to the sluggish kinetics of anodic hydrogen oxidation reaction (HOR). Balancing the adsorption/desorption ability toward H* and OH* is considered to be an efficient way to improve the HOR efficiency, but is extremely hard on one active site. Here, single metal atoms (M-sa) anchored on W2CO2 MXene (W2CO2-M-sa) were built, including a series of 3d, 4d, and 5d metals. First-principles calculations indicate that the charge transfer between M-sa and W2CO2 induces an efficient dual-active site, i.e., M-sa as the OH* active site and its adjacent O atoms as the H* active site. The dual active sites on W2CO2-M-sa can not only avoid the competitive adsorption of H* and OH* but also display a synergistic catalytic effect towards the HOR. Remarkably, W2CO2-M-sa (M-sa = Mn, Fe, Co, Ir, and Pt) shows both high stability and superior HOR activity over bulk Pt, suggesting their huge potential as anodic electrocatalysts for AEMFCs.

Automated summary

In this study, we found that single metal atoms anchored on W2CO2 MXene can create efficient dual-active sites, thereby improving the efficiency of the anodic hydrogen oxidation reaction in alkaline exchange membrane fuel cells.