New hybrid material boosts hydrogen production by five-fold
Researchers have engineered a three-dimensional composite material that dramatically improves how efficiently light converts water into hydrogen fuel. By combining graphene with specially engineered zinc indium sulfide, the material achieves hydrogen generation rates competitive with existing commercial catalysts—a key step toward making solar hydrogen production economically viable at scale.
Originaltitel: Defect and Donor Manipulated Highly Efficient Electron-Hole Separation in a 3D Nanoporous Schottky Heterojunction
<p>Given the rapid recombination of photogenerated charge carriers and photocorrosion, transition metal sulfide photocatalysts usually suffer from modest photocatalytic performance. Herein, S-vacancy-rich ZnIn<sub>2</sub>S<sub>4</sub> (V<sub>S</sub>-ZIS) nanosheets are integrated on 3D bicontinuous nitrogen-doped nanoporous graphene (N-npG), forming 3D heterostructures with well-fitted geometric configuration (V<sub>S</sub>-ZIS/N-npG) for highly efficient photocatalytic hydrogen production. The V<sub>S</sub>-ZIS/N-npG presents ultrafast interfacial photogenerated electrons captured by the S vacancies in V<sub>S</sub>-ZIS and holes neutralization behaviors by the extra free electrons in N-npG during photocatalysis, which are demonstrated by in situ XPS, femtosecond transient absorption (fs-TA) spectroscopy, and transient-state surface photovoltage (TS-SPV) spectra. The simulated interfacial charge rearrangement behaviors from DFT calculations also verify the separation tendency of photogenerated charge carriers. Thus, the optimized V<sub>S</sub>-ZIS/N-npG 3D hierarchical heterojunction with 1.0 wt % N-npG exhibits a comparably high hydrogen generation rate of 4222.4 μmol g<sup>–1</sup> h<sup>–1</sup>, which is 5.6-fold higher than the bare V<sub>S</sub>-ZIS and 12.7-fold higher than the ZIS without S vacancies. This work sheds light on the rational design of photogenerated carrier transfer paths to facilitate charge separation and provides further hints for the design of hierarchical heterostructure photocatalysts.</p>