Multimetallic Nano-Oxides as Co-Catalysts of an Fe Molecular Catalyst for Enhanced H2 Production from HCOOH: Thermodynamic and Nanostructural Insights

Renewable H2 production emerges as a forward-looking technology towards green energy transition. Herein, we present a study on novel multimetallic nano-oxides used as co-catalysts for H2 production via HCOOH dehydrogenation (FADH) by an FeII(Polyphosphine) molecular catalyst, under near-ambient P, T conditions. The co-catalyst nano-oxides consist of multimetallic {LaSrCrFeO} and {LaSrCrFeVO} perovskites, produced by flame spray pyrolysis (FSP) technology. Kinetic catalytic H2 evolution data show that both {LaSrCrFeO} and {LaSrCrFeVO} significantly boost H2 via co-catalytic action. Arrhenius analysis reveals that they decrease the rate-limiting activation energy, Ea. Specifically, Ea = 77.4 kJ mol−1 of {Fe2+/PP3} catalyst is decreased to Ea = 67.8 kJ mol−1 in {LaSrCrFeO + Fe2+/PP3} and Ea = 56.2 kJ mol−1 in {LaSrCrFeVO + Fe2+/PP3} catalyst. These significant thermodynamic effects are not observed when the simple parental oxides are used. The present findings are discussed in the context of a boosting role {LaSrCrFeO} and {LaSrCrFeVO} to the key catalytic intermediates of the FeII(Polyphosphine) catalyst. Technology-wise, this work exemplifies a novel strategy for the industrial production of co-catalysts using FSP technology within the in-situ H2 production landscape.