Heterogeneous Electrocatalysts for Efficient Water Oxidation Derived from Metal Phthalocyanine

Abstract

Abstract Designing an efficient electrocatalytic system for water splitting with high stability using low‐cost materials and simple methods is highly demanded for application in chemical energy conversion. Here, we show active water oxidation catalysis using surface immobilized Co and Ni‐based heterogeneous electrocatalytic assemblages, by the conversion of molecular precursors into more efficient heterogeneous phase electrocatalysts. The inorganic nanostructured electrocatalysts are developed by simple low‐temperature surface spraying from homogeneous CoPc and NiPc solutions following short time heat treatment at 350°C and 500°C. On NiO x and CoO x based electrocatalysts (CoO x500 @FTO, NiO x350 @FTO) derived from CoPc and NiPc molecular precursors, oxygen evolution initiates at 1.54 V (vs. RHE) [η=310 mV] and 1.55 V (vs. RHE) [η=320 mV], respectively. The electrocatalysts also show good stability during repetitive potential scans under alkaline conditions. Each of catalyst under study produces remarkable current densities just at an overpotential of η=0.45 V during long‐term water electrolysis experiments conducted for 12 hours. It illustrates the high stability of as‐deposited catalyst under harsh oxidative conditions. This unique slant provides a simplistic way for transformation of molecular catalyst into nanoscale catalyst using a much lower amount of molecular precursor.