Carbon Fiber Cloth Loaded Core-shell Structured Pd@AgCl-Ag as An Efficient Bifunctional Electrode for Direct Hydrogen Peroxide-Hydrogen Peroxide Fuel Cells

A bifunctional Pd@AgCl-Ag/O-CFC electrode was prepared on oxidized carbon fiber cloth (O-CFC) by hydrothermal method and Galvanic reaction and used for catalytic H2O2 reduction reaction (HPRR) and oxidation reaction (HPOR). The catalyst on electrode surface presents a particular core-shell structure with Ag and AgCl as the core and Pd and AgCl as the shell, facilitating the synergistic interaction between the bimetals and the exposure of the primary active substance of Pd. The Pd@AgCl-Ag/O-CFC electrode exhibited excellent catalytic performance for both HPRR and HPOR with current densities of -733.3 mA cm-2 and 708.0 mA cm-2, respectively. For the kinetic study, the activation energy of HPRR catalyzed by the Pd@AgCl-Ag/O-CFC electrode was low (7.59 kJ mol-1), and both the electroreduction and electrooxidation reaction processes were controlled by a hybrid of substance diffusion and kinetics. The electroreduction and electrooxidation reactions of H2O2 on the surface of the Pd@AgCl-Ag/O-CFC electrode are both irreversible processes, and their reaction levels are 1 and 0.5, respectively. The direct hydrogen peroxide-hydrogen peroxide fuel cell (DPPFC) was assembled with Pd@AgCl-Ag/O-CFC as a bifunctional electrode, and the open circuit potential reached 0.75 V and power density reached 61.9 mW cm-2 at 338.15 K. In addition, due to the stability of the structure and catalytic performance of the Pd@AgCl-Ag/O-CFC electrode, the DPPFC can operate stably for a long time. This work indicates that the as-prepared Pd@AgCl-Ag/O-CFC can be a promising electrode for DPPFC.