Hydrogen peroxide (H ₂ O ₂ ) is a crucial chemical used in numerous industrial applications, yet its manufacturing relies on the energy‐demanding anthraquinone process. Solar‐driven synthesis of H ₂ O ₂ is gaining traction as a promising research area, providing a sustainable method for its production. Herein, a controllable activation of n → π* electronic transition is presented to boost the photocatalytic H ₂ O ₂ evolution in ionic carbon nitrides. This enhancement is achieved through the simultaneous introduction of structural distortions and defect sites (─C ≡ N groups and N vacancies) into the KPHI framework. The optimal catalyst ( 2%Ox‐ KPHI) reached an apparent quantum yield of 41% at 410 nm without the need for any cocatalysts, outperforming most previously reported carbon nitride‐based photocatalysts. Extensive experimental characterizations and theoretical calculations confirm that a corrugated configuration and the presence of defects significantly broaden the light absorption profile, improve carrier separation and migration, promote O ₂ adsorption, and lower the energy barriers for H ₂ O ₂ desorption. Transient absorption spectroscopy indicates that the enhanced photocatalytic performance of 2%Ox ‐KPHI is largely attributed to the preferential migration of electrons at defect sites over extended timescales, following the diffusion of geminate carriers across the PHI sheets.

Solar‐driven photocatalysis employing particulate semiconductors represents a promising approach for sustainable production of valuable chemical feedstock. Metal poly(heptazine imide) (MPHI), a novel 2D ionic carbon nitride, has been recognized as an emerging photocatalyst with distinctive properties. In this minireview, we first delineate the forefront innovations of MPHI photocatalysts, spanning from synthetic strategies and solving structures to the exploration of novel properties. We place special emphasis on the structural design principles aimed at developing high‐performance MPHI systems toward photocatalytic solar fuel production such as H₂ evolution, H₂O oxidation, H₂O₂ production and CO₂ reduction. Finally, we discuss crucial insights and challenges in leveraging highly active MPHIs for efficient solar‐to‐chemical energy conversion.

We construct a carbon/KPHI heterostructure for high-performance photocatalytic H ₂ and H ₂ O ₂ evolution. The optimal 0.3Ad/KPHI hybrid showed an outstanding H ₂ evolution rate of 738 μmol h ⁻¹ g _cat ⁻¹ and H ₂ O ₂ production rate of 3.94 mmol h ⁻¹ g _cat ⁻¹ .

This perspective briefly reviews recently developed water splitting electrocatalyst materials and discusses their utilization as cocatalysts for photocatalytic and photoelectrochemical water splitting systems.

A facile and energy saving method to produce high quality ZnO nanostructures in ultrapure water for efficient perovskite solar cells.