(245h) The Interplay between Structures and Electrochemical Properties for Double Atom Doped Cobalt Oxyhydroxide Catalysts for Benzyl Alcohol Oxidation with Long-Term Stability

Global warming, environmental pollution, and energy crisis have fostered increased development towards energy generation and storage with zero carbon emissions. Green synthesis hydrogen gas by electrochemical splitting of water offers a cleaner alternative to fossil fuels. However, the standard thermodynamic potential required for water splitting is relatively high; 1.23 V. This is as a result of the energy-intensive oxygen evolution reaction (OER); a 4-electron transfer process and the inefficiency of electrocatalysts. The reduced energy requirement of electrocatalytic alcohols oxidation (AOR), especially benzyl alcohol offers a better alternative to OER for H₂ synthesis and the generation of valuable products at the anode. Transition metal oxyhydroxides, MOOH, exhibits excellent activity towards electrocatalytic anodic oxidation such as AOR due to their optimized M^2+δ-OH bond strength, abundant active sites on their surfaces and edges, and mixed valence states. However, MOOH catalysts anodic electrochemical performance are still inferior to state-of-the-art catalyst like Iridium (IV) oxide, which are expensive and not durable for long electrochemical reactions. Metal doping offers a way to improve the electrochemical properties of oxyhydroxides by synergy. This work analyzes improving the activity of pristine CoOOH by heterogenous doping with Ni and Mn under anodic bias for benzyl alcohol oxidation to benzoic acid. STEM-EDS Mappings showed homogenous distributions of Co, Mn and Ni on Nickel foam substrate. The doped catalyst showed better anodic activity than individual CoOOH, with superior durability for 24h chronoamperometry test. SEM characterization of pristine and cycled catalysts showed no significant change, validating its durability. Doping with Ni and Mn reduced the potential required by 80mV and 110mV for Benzyl alcohol oxidation reaction (BAOR) and oxygen evolution reaction (OER) respectively. High-performance liquid chromatography (HPLC) analysis of doped catalyst also showed improved electrochemical properties with over 90% yield of benzoic acid over a 24h chronoamperometry test at 1.5V vs RHE.