Facile surface reconstructions of cobalt-copper phosphide heterostructures enable efficient electrocatalytic glycerol oxidation for energy-saving hydrogen evolution

The glycerol oxidation reaction (GOR) affords an energetically more favorable route for assisted H2 production compared to the oxygen evolution reaction, with concurrent anodic value-added chemical generation. Herein, a self-supported CoP-Cu3P composite on carbon cloth (CoP-Cu3P/CC) has been fabricated, which exhibits excellent activity toward the GOR, requiring a low applied potential of 1.13 V (vs. reversible hydrogen electrode) to reach 10 mA cm-2. Through combined surface elemental analysis, cyclic voltammetry, and in situ Raman spectroscopy characterizations, we reveal that metal elements in the mixed phosphide phases interact synergistically, leading to facilitated surface reconstruction and improved electrochemical activity. We further develop an electrolytic cell where the GOR is paired with the hydrogen evolution reaction using CoP-Cu3P/CC as both the anode and cathode, which only needs the application of 1.21 V to reach a geometric current density of 10 mA cm-2. This work provides a facile strategy to couple glycerol upgrading in an energy-saving water electrolysis system. Synergistic interaction between CoP and Cu3P enables facile surface reconstruction of CoP-Cu3P nanocomposites, making them excellent glycerol oxidation and hydrogen evolution catalysts, requiring only 1.21 V to reach 10 mA cm-2.