Optimization of the IO3 polar group of BiOIO3 by bulk phase doping amplifies pyroelectric polarization to enhance carrier separation and improve the pyro-photo-electric catalytic performance

The internal polarization field generated by spontaneous polarization of pyroelectric materials is an effective means of separating electrons and holes in the pyroelectric catalysis. And the polar group is the key to the intensity of material polarization. In this paper, the effect of the introduction of polar groups by N on the pyro-photo-electric catalytic performance of the BiOIO3 is investigated for the first time and the mechanism of action is analyzed. The current density of the N introduced BiOIO3 photoanode reached up to 0.108 μA cm−2 at 1.23 V vs. RHE under the excitation of temperature change, which is twice as high as that of the bare BiOIO3. The current density is further increased to a maximum value of 0.187 μA cm−2 at 1.23 V vs. RHE after the introduction of light. Detailed experimental studies and theoretical calculations show that the substitution of O at the V3 position in the polar group of IO3 by an N atom results in a change in the polar structure. This change not only amplifies the internal polarization field and thus promotes carrier separation, but also optimizes the pyro-photo-electric catalytic efficiency. This way of direct action on the polar group provides reference for further studies on the macroscopic polarization of polar materials and offers optimization idea for the field of pyro-photo-electric catalysis.