Tafel Analysis Guided Optimization of ZnNP-O-C Catalysts for the Selective 2-Electron Oxygen Reduction Reaction in Neutral Media.

ABSTRACT

The lack of characterizations of the adsorption capability toward intermediates during reactions causes difficulties in determining the structural optimization principle of the catalysts for the 2-electron oxygen reduction reaction (2e- ORR). Here, a Tafel-θ method is proposed to evaluate the surface coverage (θ) of important intermediates (*OOH and *OH) on the material surface and further help optimize the catalyst. With the assistance of Tafel-θ analysis, a Zn nanoparticle incorporated oxygen-doped carbon (ZnNP-O-C) catalyst with high 2e- ORR performance (onset of ∼0.57 V and selectivity of >90.4%) in neutral media was achieved. Both the theoretical calculation and characterization results are consistent with the Tafel-θ deduction, revealing that an appropriate ratio of Zn nanoparticles and bridging O can optimize the *OOH adsorption/desorption strength of the adjacent carbon site. This study not only provides an advanced ZnNP-O-C catalyst for electrochemical H2O2 production but also proposes a fast and precise method for the comprehensive assessment of future catalysts.