Novel strategy for efficient water splitting through pyro-electric and pyro-photo-electric catalysis of BaTiO₃ by using thermal resource and solar energy

The use of renewable energies to produce hydrogen is an important issue in recent decades. Herein, the pyro-electric catalysis is firstly investigated by combining pyroelectric effect and electrochemical catalysis on pyroelectric BaTiO₃ electrodes for realizing water splitting under thermal gradient excitation. On this basis, the pyro-photo-electric catalysis is proposed by coupling pyroelectric and photoelectrochemical catalysis to enhance the performance of the photoanode in water splitting for the first time. The current density of BaTiO₃ under cold-hot alternation and illumination increases to 0.38 mA cm⁻² at 1.23 V vs. RHE, obviously higher than the sum of photocurrent (0.17 mA cm⁻²) and pyroelectric current (0.13 mA cm⁻²). The improvement of the performance is not only owing to the generation of photo-generated and pyro-generated carriers, but due to the boosted charge separation caused by band alignment. This work indicates a novel strategy of pyro-electric catalysis and pyro-photo-electric catalysis by using BaTiO₃ nanorods, realizing the synergetic utilization of multi-energy, including solar energy and thermal resource, which provides a practical method in designing the electrodes with excellent catalytic performance.