Enhanced electrocatalysis of 3 D structured array electrodes for energy-efficient hydrogen production by a negative thermal expansion film

Temperature is extremely significant for electrocatalysis, but heat will cause deformation and failure of catalysts. To intensify reaction and decrease thermal deformation for hydrogen production, Ni3S2 nanorods (NS NRs) arrays were prepared by electrochemical co-deposition, dealloying and vulcanization, and further covered with a film of a negative thermal expansion (NTE) material of Al2(WO4)3 via a facile deposition method to obtain rod@shell three-dimensional (3 D) structured Ni3S2@Al2(WO4)3 (NSAW) NRs catalysts which connect a nickel substrate without binder. The physicochemical properties and electrocatalytic performance of the as-obtained NRs were evaluated using various techniques, and the enhanced mechanism was proposed based on multifarious results under different conditions. The hydrogen production rate of NSAW is increased 61% as temperature increases from 25 to 95 °C. Compared to the NS NRs, the hydrogen evolution reaction (HER) overpotential at 10 mA/cm2 is reduced to about 95 mV at 95 °C, and the Rct is decreased 84.7%, while the Faraday current efficiency is improved to 86.2%. Al2(WO4)3 protects NS well from breakdown during cycles in heating circumstances to improve catalytic performance and long-term stability. The work supplies an effective strategy to enhance the performance of catalysts at high temperature. [Display omitted] •High-temperature catalysis performance of Ni3S2 is significantly improved by a NTE film.•3 D structured rod@shell array catalysts on a metal substrate are successfully synthesized via a facile way.•Al2(WO4)3 obviously improves the thermal stability, hydrogen evolution activity and stability of Ni3S2.•Al2(WO4)3 greatly prevents the breakdown of Ni3S2 electrode during cycles under different conditions.•Enhancement mechanism of Ni3S2 by Al2(WO4)3 is proposed.