Oxygen-rich ligands tailored for novel metal–organic gel electrocatalyst to promote two-electron selectivity electrocatalysis

Abstract

More extensive attention has been garnered about the H2O2 electroproduction via two-electron oxygen reduction reaction (2e- ORR). Aiming to develop a more active, more selective and more stable catalyst, herein we reported an unconventional raw metal–organic gels (MOGs) toward this process. This pioneering work, by ingeniously designing and altering the precursor ligands, achieving precisely controlling the number of oxygen groups (OGs). By elaborately comparing more than 70 samples, uncovered the significance that OGs could sufficiently promote the selectivity for H2O2 electrochemical synthesis through the two-electron pathway (realizing enhancement more than 20% in this work). The most potential Fe0.1Co0.9 MOG (H6L), performing an onset potential of 0.76 V (low overpotential), a high selectivity up to 93% ranging 0.15 V to 0.65 V (large voltage window) and 2.1 electron transfer number (implying the 2e- process dominate). This study, unlike other oxidation treatment, through the precise regulation of precursors, further confirmed the feasibility of oxygen-containing functional groups (OGs) tailoring strategy, providing a possibility for low-cost and efficient potential candidate of 2e- ORR.