Photo-assisted self-optimizing of charge-carriers transport channel in the recrystallized multi-heterojunction nanofibers for highly efficient photocatalytic H2 generation

- Photo-assisted self-optimizing of charge-carriers transport channel is realized in copper species/TiO2 electrospun nanofibers.
- CuO/TiO2 nanofibers can be recrystallized to form Cu/Cu2O/CuO/TiO2 nanofibers during photocatalytic process.
- Dynamics difference of excitons migration is responsible for the self-optimization of charge-carriers transport channel.
- 40-fold enhanced H2 generation was observed on the recrystallized nanofibers during photocatalytic decomposition of formic acid.

Rational arrangement of nanosized semiconductor components in the multi-heterojunction photocatalyst can lead to the formation of a high-speed transport channel for charge-carriers separation and migration, which provides a promising way to achieve excellent photocatalytic efficiency for solar fuels generation. Herein, we develop a photo-assisted self-optimization strategy to re-build the charge-carriers transport channel in the copper species nanocrystals/TiO2 electrospun nanofibers with the organic hydrogen-carrier molecules as the photo-reactants. As a result of the dynamics difference of the excitons migration during the photocatalytic process, the binary CuO/TiO2 heterojunction nanofibers are recrystallized to form the quaternary Cu/Cu2O/CuO/TiO2 multi-heterojunction nanofibers that exhibits a higher rate constant (∼1.7×108S−1) for the interfacial electron-transfer than the former nanofibers (∼0.7×108S−1) due to the improved charge-carriers transport channel. In this way, a 40-fold enhanced H2 generation rate was observed on the recrystallized nanofibers photocatalyst during the photocatalytic decomposition of formic acid as compared to the pure TiO2 nanofibers. Our work presents an available paradigm to skillfully use a transient photo-physicochemical process to mildly engineer a high-quality charge-carriers transport channel in the hetero-nanophotocatalyst for realizing an optimal photocatalytic performance.

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