Scalable neutral H2O2 electrosynthesis by platinum diphosphide nanocrystals by regulating oxygen reduction reaction pathways

Abstract

Despite progress in small scale electrocatalytic production of hydrogen peroxide (H2O2) using a rotating ring-disk electrode, further work is needed to develop a non-toxic, selective, and stable O-2-to-H2O2 electrocatalyst for realizing continuous on-site production of neutral hydrogen peroxide. We report ultrasmall and monodisperse colloidal PtP2 nanocrystals that achieve H2O2 production at near zero-overpotential with near unity H2O2 selectivity at 0.27V vs. RHE. Density functional theory calculations indicate that P promotes hydrogenation of OOH* to H2O2 by weakening the Pt-OOH* bond and suppressing the dissociative OOH* to O* pathway. Atomic layer deposition of Al2O3 prevents NC aggregation and enables application in a polymer electrolyte membrane fuel cell (PEMFC) with a maximum r(H2O2) of 2.26mmolh(-1) cm(-2) and a current efficiency of 78.8% even at a high current density of 150mAcm(-2). Catalyst stability enables an accumulated neutral H2O2 concentration in 600mL of 3.0wt% (pH = 6.6). The synthesis of high concentration H2O2 from water and oxygen at moderate conditions could provide an on-site H2O2 source for medical and water purification applications. Here, authors show Al2O3-stabilized PtP2 nanocrystals to enable selective, stable and efficient neutral pH H2O2 production.