High efficient PEC performance via mechanical stress field and temperature field coupling assisted Ba0·7Sr0·3TiO3 under visible light irradiation

Abstract

Limited carriers migration and separation efficiency are key factors affecting the photo-electric catalysis performance of semiconductors. In this paper, the mechanical stress field and temperature field are combined to realize the piezo-pyro-photo-electric catalysis by using the coupling effect of the two external fields, which greatly improves the catalysis performance of Ba0·7Sr0·3TiO3 semiconductor. At 20–50 °C alternating heating and cooling, ultrasonic excitation, light and bias conditions, the current density of Ba0·7Sr0·3TiO3 increased to 1.01 mA cm−2. It is 1.22 and 1.31 times higher than that of piezo-photo-electric catalysis (0.83 mA cm−2) under single mechanical stress field and pyro-photo-electric catalysis (0.77 mA cm−2) under temperature field, respectively. The coupled external stimulation is beneficial to the improvement of photo-electric catalysis performance. Due to the presence of polarization charge imbalance and piezoelectric/pyroelectric polarization induced built-in electric field piezoelectric/pyroelectric potential, thereby increasing the total concentration of carriers, accelerating the separation and transfer efficiency of carriers. This study realizes the synergistic utilization of various clean energy sources such as solar energy, thermal energy, mechanical energy and electrical energy, and provides a key idea for designing electrodes with excellent catalytic performance.