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.