To conveniently regulate photocatalytic reactions, the design and development of smart photocatalysts, which can realize a series of controllable regulation of their structure, physicochemical properties, photocatalytic activity, and selectivity by simple external stimuli, such as chemical substances, pH, light, electric field, and heat, has aroused keen interest. However, the relevant research is still in its infancy. Herein, a smart imine covalent-organic-framework (COF) photocatalyst HP-n (n represents the pH of COF pretreatment, n = 1∼7) with proton-initiated switchable photocatalytic aerobic oxidation has been prepared. In the structure, the imine units can be reversibly protonated, which leads to the COF skeleton rearrangement from the phenolic to its quinone structure. The corresponding absorption band edge is expanded from 463 nm (HP-7) to 630 nm (HP-1). Meanwhile, the excitation energy transfer, oxygen adsorption, and activation change significantly, endowing HP-n with smartly switchable 1O2 production and interesting proton-initiated efficiency photocatalytic sulfide oxidation with both conversion and sulfoxide selectivity >99%. This work demonstrates a smart imine-COF photocatalyst, which paves the way for the development of smart photocatalysts and reveals the critical roles of protons in the structure–property–activity relationship of COF photocatalysts.

Active species regulation is a key scientific issue that essentially determines the selectivity and activity of a photocatalyst. Herein, Cu I -bridged tetrakis(4-ethynylphenyl)ethene aggregates (T 4 EPE-Cu) with photo-regulated 1 O 2 and O 2 *À generation were demonstrated for selective photocatalytic aerobic oxidation. In this system, transient photovoltage combined with the density functional theory calculations confirmed that Cu-alkynyl was the main oxygen activation site. The adsorbed O 2 tends to produce O 2 *À because of the potential well effect of Cu-alkynyl under highenergy light excitation. But under low-energy light, O 2 tends to produce 1 O 2 via resonance energy transfer with Cualkynyl. For α-terpinene oxidation, the ratios of 1 O 2 products to O 2 *À products can be controlled from 1.3 (380 nm) to 10.7 (600 nm). Furthermore, T 4 EPE-Cu exhibited ultrahigh photocatalytic performance for Glaser coupling and benzylamine oxidation, with a conversion and selectivity of over 99 %.

Active species regulation is a key scientific issue that essentially determines the selectivity and activity of a photocatalyst. Herein, CuI‐bridged tetrakis(4‐ethynylphenyl)ethene aggregates (T4EPE‐Cu) with photo‐regulated 1O2 and O2.− generation were demonstrated for selective photocatalytic aerobic oxidation. In this system, transient photovoltage combined with the density functional theory calculations confirmed that Cu‐alkynyl was the main oxygen activation site. The adsorbed O2 tends to produce O2.− because of the potential well effect of Cu‐alkynyl under high‐energy light excitation. But under low‐energy light, O2 tends to produce 1O2 via resonance energy transfer with Cu‐alkynyl. For α‐terpinene oxidation, the ratios of 1O2 products to O2.− products can be controlled from 1.3 (380 nm) to 10.7 (600 nm). Furthermore, T4EPE‐Cu exhibited ultrahigh photocatalytic performance for Glaser coupling and benzylamine oxidation, with a conversion and selectivity of over 99 %.

The defect engineering has become a promising strategy to tailor the specific surface area, energy band structure and photocatalytic properties of catalysts. Thus, a series of oxygen defect modified polyimide...