Fabrication, Characterization, and Photoelectrochemical Properties of Cu‐Doped PbTiO₃ and Its Hydrogen Production Activity

Abstract

We report herein the fabrication of visible‐light responsive n‐type PbTiO3 by a combustion method and p‐type Cu‐doped PbTiO3 by an impregnation method to improve hydrogen production activity. Copper was doped into the PbTiO3 lattice up to 1 wt %; any further increase in the loading resulted in the formation of CuO on the surface of the sample. Photoluminescence confirmed that 1 wt % Cu‐doped PbTiO3 effectively suppressed the defects in PbTiO3, which helped to reduce the recombination rate of the photoinduced charge carriers. The prepared PbTiO3 photocatalyst behaves as an n‐type semiconductor, whereas 1 wt % Cu‐doped PbTiO3 behaves as a p‐type semiconductor. The photocatalytic hydrogen production activity of PbTiO3 increased with increasing Cu content up to 1 wt % and thereafter decreased upon further loading. The 1 wt % Cu‐doped PbTiO3 sample showed higher activity for hydrogen liberation than pristine PbTiO3 (2.5 times) and all of the other CuO‐loaded samples. The energy conversion efficiency of 1 wt % Cu‐doped PbTiO3 was 5.95 % for hydrogen production under visible‐light irradiation. The enhanced hydrogen production activity of Cu‐doped PbTiO3 was discussed on the basis of optimum copper doping, photoluminescence intensity, and their band‐edge positions. However, the higher activity of CuO‐loaded (>1 wt %) PbTiO3 relative to that of neat PbTiO3 is perhaps a result of the extensive light absorption properties of the CuO nanoparticles, which help to generate more electron–hole pairs on the surface.

Synergetic effect of copper species as cocatalyst on LaFeO3 for enhanced visible-light photocatalytic hydrogen evolution

“…The PL emission intensities of the treated LaFe 0.8 þ LaCu 0.2 samples were weaker than those of the untreated LaFe 0.8 þ LaCu 0.2 , and they gradually decreased as the reduction temperature increased from 250 C to 500 C. This indicates that the presence of metallic Cu species helps to reduce the recombination rate of photo-induced charge carriers. Because the PL emission is the result of the recombination of excited electrons and holes, the lower PL intensity of the samples indicates a lower recombination rate [32]. Table 2 shows the rates of H 2 evolution on LaFe 0.8 þ LaCu 0.2 treated at various temperatures together with the rates on LaFeO 3 and La 2 CuO 4 for comparison.…”

Preparation and photocatalytic performance of TiO2/PbTiO3 fiber composite enhanced by external force induced piezoelectric field

“…The other two fitted peaks Ti 2p 2 and Ti 2p 4 are located at 458.7 and 464.1 eV, respectively, which indicating the Ti 4+ in TiO 2 . Compared with the related binding energy of Ti 2p(3/2) reported in the literature, Ti 2p(3/2) in TiO 2 shows a slight negative shift, indicating the electrons are transferred from PbTiO 3 to TiO 2 . The presence of Pb(VI) and electrons transferred from PbTiO 3 to TiO 2 confirm that a heterojunction is formed at the interface between TiO 2 and PbTiO 3 .…”

“…In the XPS spectrum of Ti 2p (Figure C), the two fitted peaks Ti 2p 1 and Ti 2p 3 for Ti 2p(3/2) and Ti 2p(1/2) are located at 458.0 and 464.0 eV, respectively, indicating the Ti 4+ in PbTiO 3 . The other two fitted peaks Ti 2p 2 and Ti 2p 4 are located at 458.7 and 464.1 eV, respectively, which indicating the Ti 4+ in TiO 2 . Compared with the related binding energy of Ti 2p(3/2) reported in the literature, Ti 2p(3/2) in TiO 2 shows a slight negative shift, indicating the electrons are transferred from PbTiO 3 to TiO 2 .…”

Photocatalytic Degradation of Congo Red Using PbTiO3 Nanorods Synthesized via a Sonochemical Approach

“…Strong and sharp diffraction peaks indicate that the as‐synthesized sample is well crystallized. Apart from this, the impurity peak was not seen, which confirmed that the as‐synthesized sample successfully prepared single phase with high purity ,. By applying the Scherrer formula for the high‐intensity peak (101) plane, the crystallite size of PbTiO 3 was determined via X‐ray diffraction data by applying the following relation…”

“…Further the most important peak in O(1 s) region (see fig. 3(d)) at 527.1 eV i. e. most intense peak at smaller binding energy is attributed to lattice oxygen (Ti−O band), whereas the minor peak at 529.5 eV (higher binding energy) is assigned to surface oxygen, that is very usual in sample with high surface energy ,,,…”