Laser patterned and bifunctional Ni@N-doped carbon nanotubes as electrocatalyst and photothermal conversion layer for water splitting driven by thermoelectric device

Abstract For efficient conversion from solar energy to hydrogen energy, the integrated system between light absorbing unit and water splitting unit is in the spotlight. Herein, we presented a bifunctional Ni@NCNTs/NF-L as both photothermal conversion layer integrated with thermoelectric generator (TE) and efficient hydrogen evolution reaction (HER) electrocatalyst to reducing the potential, realizing the integration system for overall water splitting. The Ni nanoparticles embedded into N-doped carbon nanotubes (Ni@NCNTs/NF-L) with various patterns are prepared by controllable laser processing and gas-solid calcination reaction. Furthermore, iron nickel oxides nanoparticles on NiFe alloys foil (NiFe-L) are obtained by laser ablation, which are applied for the oxygen evolution reaction (OER) electrode to establish two electrode electrolyzer of (−) Ni@NCNTs/NF-L/TE // NiFe-L (+) for overall water splitting. Integrating with one TE, the voltage of water splitting at the current-density of 50 mA cm−2 reduced from 1.947 V to 1.213 V under the standard AM 1.5 G illumination. The integrated thermoelectric device plays a doubtless role to realize solar energy driving overall water splitting with integration and patterning fabrication in large-scale.