Full spectrum solar hydrogen production by tandems of perovskite solar cells and photothermal enhanced electrocatalysts

Among various methods of hydrogen production, water splitting driven by perovskite solar cell (PSC) is highly desirable due to the abundance of solar energy and low material cost. The key to achieve higher solar-to-hydrogen (STH) conversion efficiency is to reduce the overpotential of water splitting and enhance the solar energy utilization of the system. Herein, we demonstrate a photothermal enhanced oxygen evolution reaction (OER) electrocatalyst by depositing NiFe layer double hydroxide (NiFe LDH) on a three-dimensional carbon nanotubes (CNTs) scaffold. The CNTs can serve double functions, first as a conductive support of the catalyst to effectively transport charge, second as a photon absorber to induce photothermal effect to enhance OER activity. The photothermal enhancement of OER is demonstrated with infrared irradiation, part of the solar spectrum that is normally wasted in a conventional photovoltaic-electrolysis water splitting system. Based on the superior OER activity and photothermal properties, an unbiased water splitting system is constructed by integrating a CNTs@NiFe LDH//Pt/C electrochemical cell (EC) with a semitransparent perovskite solar cell (ST-PSC) mini-module in tandem configuration. The ST-PSC module provides voltage to drive water splitting and transmits infrared light to the rear CNTs@NiFe LDH electrode to induce the photothermal effect. The integrated PSC-EC system improves the STH efficiency from 11.7% to 13.2% with assistance of the photothermal effect and demonstrates a new strategy to harvest the full spectrum of solar irradiation for hydrogen production.