Water Oxidation by Copper–Amino Acid Catalysts at Low Overpotentials. Issue 12 (19th May 2016)

• Record Type: Journal Article
• Authors: Lu, Cui; Wang, Jianying; Chen, Zuofeng
• Is Part Of: ChemCatChem. Volume 8:Issue 12(2016)
• Page Start: 2165
• Page End: 2170
• Publication Date: 2016-05-19
• Subjects: amino acids -- copper -- glycine -- heterogeneous catalysis -- water oxidation; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201600261
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Although notable progress has been made in developing first‐row transition‐metals‐based water oxidation catalysts, continuous efforts are required to identify more inexpensive, efficient, and robust catalysts. Here, we demonstrate the utility of a series of readily available complexes formed by earth‐abundant copper and amino acids as catalyst precursors. In phosphate solution at pH 12, electrolysis with 1 mm Cu II and 4 mm Gly results in in situ formation of an amorphous surface precipitate of a CuO/Cu(OH)2 mixture, which incorporates a substantial amount of phosphate anions. This surface‐bound solid can catalyze water oxidation with an impressive onset overpotential of 380 mV, an overpotential of 450 mV for a current density of 1 mA cm −2, and a low Tafel slope of 64 mV dec −1, which make it among the most active Cu‐based heterogeneous electrocatalysts. The copper‐based reactivity toward water oxidation is shared by Cu II complexation to other amino acids as catalyst precursors. Abstract : Cu‐based water oxidation catalysts : A self‐assembling Cu II –4 Gly complex is reported as a catalyst precursor for water oxidation. Electrolysis with this complex precursor results in in situ formation of a surface‐accumulated copper(II) deposit, dominated by an amorphous, phosphate‐incorporated CuO/Cu(OH)2 mixture. An onset overpotential of 380 mV and a current density of 1 mA cm −2 could be achieved at an overpotential of 450 mV with a Tafel slope of 64 mV dec −1 .