Photocatalytic CO₂ conversion promises an ideal route to store solar energy into chemical bonds. However, sluggish electron kinetics and unfavorable product selectivity remain unresolved challenges. Here, an ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate, and borate-anchored Co single atoms were separately loaded on ultrathin g-C₃N₄ nanosheets. The optimized nanocomposite photocatalyst produces CO and CH₄ from CO₂ and water under UV–vis light irradiation, exhibiting a 42-fold photoactivity enhancement compared with g-C₃N₄ and nearly 100% selectivity towards CO₂ reduction. Experimental and theoretical results reveal that the ionic liquid extracts electrons and facilitates CO₂ reduction, whereas Co single atoms trap holes and catalyze water oxidation. More importantly, the maximum electron transfer efficiency for CO₂ photoreduction, as measured with in-situ μs-transient absorption spectroscopy, is found to be 35.3%, owing to the combined effect of the ionic liquid and Co single atoms. This work offers a feasible strategy for efficiently converting CO₂ to valuable chemicals.

Realization of solar‐driven aerobic organic transformation under atmospheric pressure raises the great challenge for efficiently activating O₂ by tailored photocatalysts. Guided by theoretical calculation, phosphate groups are used to induce the construction of ultrathin Co phthalocyanine/g‐C₃N₄ heterojunctions (CoPc/P‐CN, ≈4 nm) via strengthened H‐bonding interfacial connection, achieving an unprecedented 14‐time photoactivity improvement for UV–vis aerobic 2,4‐dichlorophenol degradation compared to bulk CN by promoted activation of O₂. It is validated that more ^•O₂⁻ radicals are produced through the improved photoreduction of O₂ by accelerated photoelectron transfer from CN to the ligand of CoPc and then to the abundant single Co–N₄ (II) catalytic sites, as endowed by the matched dimension, intimate interface even at the molecular level, and high CoPc dispersion of resulted heterojunctions. Interestingly, CoPc/P‐CN also exhibits outstanding photoactivities in the aerobic oxidation of aromatic alcohols. This work showcases a feasible route to realize efficient photocatalytic O₂ activation by exploiting the potential of ultrathin metal phthalocyanine (MPc) assemblies with abundant single‐atom sites. More importantly, a universal facile strategy of H‐bonding‐dominating construction of MPc‐involved heterojunctions is successfully established.

Due to the gradual depletion of fossil fuel reserves on the earth and increasing pollution in the environment, it is highly desirous to develop renewable technologies for clean energy production and environmental remediation through extensively employing semiconductor photocatalysis. With regard to efficient photocatalysis, apart from charge separation, possessing sufficient thermodynamic abilities are the prerequisites so that the photogenerated electrons and holes can induce redox reactions. For most visible-light-responsive semiconductor photocatalysts, photogenerated holes exhibit strong oxidation ability because of their appropriate valence band top levels. However, the ability of the photogenerated electrons to induce reduction reactions is weak, generally due to their low conduction band bottom levels. Hence, a feasible strategy would involve the rational construction of a heterojunctional system with thermodynamically appropriate energy platforms as a space-separated electron shuttle for further intensifying the reduction reactions for efficient visible-light photocatalysis. Obviously, it is considerably meaningful to develop an appropriate electron energy platform-dependent efficient heterojunctional photocatalyst under visible-light irradiation and to review recent developments in this field. In this review, special emphasis is paid to bridged heterojunction-related advances made by our group, focusing upon visible-light-responsive single-metal oxides like Fe₂O₃, bimetal oxides like BiVO₄, plasmonic noble-metal nanoparticles like Au, and polymer-based nanomaterials like g-C₃N₄ as model photocatalysts. Apparently, it is imperative to design efficient nanophotocatalysts for fields related to energy production and environmental remediation from the scientific and engineering points of view.

Interface-modulated ultrathin Ni(ii) MOF/g-C₃N₄ heterojunctions exhibit greatly improved charge separation and, consequently, 18-fold photoactivity enhancement for the CO₂RR.

It is highly desired to improve the photoelectrochemical (PEC) performance of nanosized WO₃ by artificially modulating the photogenerated electrons and holes simultaneously. Herein, WO₃ nanoplates have been successfully prepared by a simple one-pot two-phase separated hydrolysis-solvothermal method, and then co-modified with RGO and phosphate acid successively by wet chemical processes. Subsequently, the as-prepared WO₃-based nanoplates were immobilized on the conductive glasses to explore the PEC activities for both water oxidation to evolve O₂ and phenol degradation. It is clearly demonstrated that the co-modified WO₃ nanoplates exhibit significantly improved PEC activities compared with pristine WO₃, especially for that with the amount-optimized modifiers by ca. 6-time enhancement. Mainly based on the evaluated hydroxyl radical amounts produced and the electrochemical impedance spectra, it is suggested that the improved PEC activities are attributed to the greatly enhanced photogenerated charge separation after chemically modification with RGO and phosphate groups to WO₃, respectively by transferring electrons as the collectors and trapping holes via the formed negative field after phosphate disassociation. This work provides a feasible synthetic strategy to improve the photoactivities of nanosized WO₃ for energy production and environmental remediation.