High-performance CoNb phosphide water splitting electrocatalyst on plasma-defect-engineered carbon cloth

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Drum-shaped CoP 3 -Nb 2 P water splitting electrocatalyst is synthesized in situ on plasma-defect engineered carbon cloth. Excellent electrocatalytic stability and activity are achieved, highlighted by the low overpotentials to generate j 10 , j 500 and j 1000 of 111, 317 and 375 mV, respectively, as well as over 50h stable operation. • Plasma defect engineering enhances electrocatalyst binding with flexible carbon support. • Plasma-modified carbon cloth supports drum-like Co-Nb phosphide catalyst. • Granular Co-Nb phosphide structure with huge electrochemically active area. • Superior electrocatalytic performance achieved with high current density. • In-situ Raman and DFT results confirm synergistic effect between Co and Nb phosphide. Herein, an efficient and stable Co-Nb bimetallic phosphide electrocatalyst for HER is successfully engineered on the dielectric barrier discharge (DBD) plasma modified carbon cloth (PCC) at ambient conditions. The resulting microsized drum-like CoP 3 -Nb 2 P catalysts supported by the PCC show high electrocatalytic activity, which only needs overpotentials of 111, 317 and 375 mV to generate current densities of 10, 500 and 1000 mA cm −2 ( j 10 , j 500 and j 1000 ) respectively. A small Tafel value of 72.8 mV dec −1 is achieved. When the current density is over j 202 , the performance of the CoP 3 -Nb 2 P/PCC surpasses commercial noble metal-based Pt/C/PCC catalysts. The current density drops only 6.4 % after 50 h I-t testing at j 100 , indicating a good electrochemical stability. Theory calculations and in-situ Raman spectra results reveal the synergistic effect between Co and Nb phosphide causes a remarkable HER performance, and the Nb-Nb vibration weakens the P-H ads bond, leading to the effective H 2 generation.