High ‐Valence W6+ Ions Boost Cr2+ Activity in CrWO4 for Ideal Water Oxidation

By identifying descriptor that explains the functionality of W-based 3d transition oxides and exploring the potential of Cr based oxides, the water splitting performance of W-based catalysts is predicted and demonstrated through simulations and electrochemical experiments. AbstractElectrocatalytic activity of multi-valence metal oxides for oxygen evolution reaction (OER) arises from various interactions among the constituent metal elements. Although the high-valence metal ions attract recent attentions due to the interactions with their neighboring 3d transition metal catalytic center, atomic-scale explanations for the catalytic efficiencies are still lacking. Here, by employing density functional theory predictions and experimental verifications, unprecedented electronic isolation of the catalytic 3d center (M2+) induced by the surrounding high-valence ions such as W6+ is discovered in multivalent oxidesMWO4 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn). Due to W6+’s extremely high oxidation state with the minimum electron occupations (d0), the surrounding W6+ blocks electron transfer toward the catalyticM2+ ions and completely isolates the ions electronically. Now, the isolatedM2+ ions solely perform OER without any assistant electron flow from the adjacent metal ions, and thus the original strong binding energies of Cr with OER intermediates are effectively moderated. Through exploiting “electron isolators” such as W6+ surrounding the catalytic ion, exploring can be do...

Source: Small - March 28, 2024 Category: Nanotechnology Authors: Chanseok Kim, Dasom Jeon, Nayeong Kim, Jungki Ryu, Jun Hee Lee Tags: Research Article Source Type: research