Element doping has been extensively attempted to develop visible-light-driven photocatalysts, which introduces impurity levels and enhances light absorption. However, the dopants can also become recombination centers for photogenerated electrons and holes. To address the recombination challenge, we report a gradient phosphorus-doped CdS (CdS-P) homojunction nanostructure, creating an oriented built-in electric-field for efficient extraction of carriers from inside to surface of the photocatalyst. The apparent quantum efficiency (AQY) based on the cocatalyst-free photocatalyst is up to 8.2% at 420 nm while the H evolution rate boosts to 194.3 μmol·h·mg, which is 58.3 times higher than that of pristine CdS. This concept of oriented built-in electric field introduced by surface gradient diffusion doping should provide a new approach to design other types of semiconductor photocatalysts for efficient solar-to-chemical conversion.

Infrared light, more than 50% of the solar light energy, is long‐termly ignored in the photocatalysis field due to its low photon energy. Herein, infrared‐light‐responsive photoinduced carriers driver is first constructed taking advantage of pyroelectric effect for enhancing photocatalytic hydrogen evolution. In order to give full play to its role, the photocatalytic reaction is localized on the surface and interface of the composite based on a new semi‐immersion type heat collected photocatalytic microfiber system. The system is consisted of distinctive pyroelectric substrate poly(vinylidene fluoride‐co‐hexafluropropylene (PVDF‐HFP), typical photothermal material carbon nanotube (CNT), and representative photocatalyst CdS. The transient photocurrent, electrochemical impedance spectroscopy, time‐resolved photoluminescence and pyroelectric potential characterizations indicate that the infrared‐light‐responsive carriers driver significantly promotes the photogenerated charge separation, accelerates carrier migration, and prolongs carrier lifetime. The photocatalytic hydrogen evolution efficiency is remarkably improved more than five times with the highest average apparent quantum yield of 16.9%. It may open up new horizons to photocatalytic technology for the more efficient use of infrared light.

The piezo-phototronic effect plays an ingenious and robust role in modulating the optoelectronic processes of photocatalysis, solar cells, photodetectors and light-emitting diodes by tuning energy band structures and photoinduced carrier behaviors.

The construction of internal electric field is generally considered an effective strategy to enhance photocatalytic performance due to its significant role in charge separation. However, static internal electric field is prone to be saturated either by inner or outer shield effect, and thus its effect on the improvement of photocatalysis can easily vanish. Here, the self-healing internal electric field is proposed and successfully endowed to a designed helical structural composite microfiber polyvinylidene fluoride/g-C 3 N 4 (PVDF/g-C 3 N 4 ) based on the bioinspired simple harmonic vibration. Importantly, the saturation and recovery of internal electric field are characterized by transient photovoltage and photoluminescence. The results indicate that the internal electric field could be saturated within about 10 min and refreshed with the assistance of rebuilt piezoelectric potential. The lifetime of photogenerated carriers is about 10 −4 s and the number of effective carriers is greatly increased in the presence of self-healing internal electric field. The results provide direct experimental evidence on the role of self-healing internal electric field in charge transfer behavior. This work represents a new design strategy of photocatalysts, and it may open up new horizons for solving energy shortage and environmental issues.