Arising from reduced dielectric screening, excitonic effects should be taken into account in ultrathin two-dimensional photocatalysts, and a significant challenge is achieving nontrivial excitonic regulation. However, the effect of structural modification on the regulation of the excitonic aspect is at a comparatively early stage. Herein, we report unusual effects of surface substitutional doping with Pt on electronic and surface characteristics of atomically thin layers of Bi3O4Br, thereby enhancing the propensity to generate 1O2. Electronically, the introduced Pt impurity states with a lower energy level can trap photoinduced singlet excitons, thus reducing the singlet–triplet energy gap by ∼48% and effectively facilitating the intersystem crossing process for efficient triplet excitons yield. Superficially, the chemisorption state of O2 causes the changes in the magnetic moment (i.e., spin state) of O2 through electron-mediated triplet energy transfer, resulting a spontaneous spin-flip process and highly specific 1O2 generation. These traits exemplify the opportunities that the surface engineering provides a unique strategy for excitonic regulation and will stimulate more research on exciton-triggering photocatalysis for solar energy conversion.

Single-atom photocatalysts have shown their fascinating strengths in enhancing charge transfer dynamics; however, rationally designing coordination sites by metal doping to stabilize isolated atoms is still challenging. Here, a one-unit-cell ZnIn 2 S 4 (ZIS) nanosheet with abundant Cu dopants serving as the suitable support to achieve a single atom Pt catalyst (Pt 1 /Cu-ZIS) is reported, and hence the metal single atom-metal dopant interaction at an atomic level is disclosed. Experimental results and density functional theory calculations highlight the unique stabilizing effect (Pt-Cu interaction) of single Pt atoms in Cu-doped ZIS, while apparent Pt clusters are observed in pristine ZIS. Specifically, Pt-Cu interaction provides an extra coordination site except three S sites on the surface, which induces a higher diffusion barrier and makes the single atom more stable on the surface. Apart from stabilizing Pt single atoms, Pt-Cu interaction also serves as the efficient channel to transfer electrons from Cu trap states to Pt active sites, thereby enhancing the charge separation and transfer efficiency. Remarkably, the Pt 1 /Cu-ZIS exhibits a superb activity, giving a photocatalytic hydrogen evolution rate of 5.02 mmol g −1 h −1 , nearly 49 times higher than that of pristine ZIS.

Due to environmentally friendly operation and on-site productivity, electrocatalytic singlet oxygen (1O2) production via O2 gas is of immense interest in environment purification. However, the side-on configuration of O2 on the catalysts surface will lead to the formation of H2O, which seriously limits the selectivity and activity of 1O2 production. Herein, we show a robust N-doped CuO (N–CuO) with Pauling-type (end-on) adsorption of O2 at the N–Cu–O3 sites for the selective generation of 1O2 under direct-current electric field. We propose that Pauling-type configuration of O2 not only lowers the overall activation energy barrier, but also alters the reaction pathway to form 1O2 instead of H2O, which is the key feature determining selectivity for the dissociation of Cu–O bonds rather than the O–O bonds. The proposed N dopant strategy is applicable to a series of transition metal oxides, providing a universal electrocatalysts design scheme for existing high-performance electrocatalytic 1O2 production.

The sluggish regeneration rate of FeII and low operating pH still restrict the wider application of classical Fenton process (FeII/H2O2) for practical water treatment. To overcome these challenges, we exploit the Mn–CNH co-catalyst to construct a solid–liquid interfacial Fenton reaction and accelerate the FeIII/FeII redox cycle at the interface for sustainably generating •OH from H2O2 activation. The Mn–CNH co-catalyst exhibits an excellent regeneration rate of FeII (∼65%) and a high tetracycline removal rate (K obs) of 0.0541 min–1, which is 19.0 times higher than that of the FeII/H2O2 system (0.0027 min–1) at a near-neutral pH (pH ≈ 5.8), and it also attains 100% degradation of sulfamethoxazole, rhodamine B, and methyl orange. The cyclic mechanism of FeIII/FeII is further elucidated in an atomic scale by combining characterizations and density functional theory calculations, including Feaq III specific adsorption and the electron-transfer process. Mn active sites can accumulate electrons from the matrix and adsorb Feaq III to form Mn–Fe bonds at the solid–liquid interface, which accelerate electron transfer from Mn–CNH to Feaq III and promote the regeneration of FeII at a wide pH range with a lower energy barrier. The regeneration rate of FeII in the Mn–CNH/FeII/H2O2 system outperforms the benchmark Fenton system and other typical metal nanomaterials, which has great potential to be widely applied in actual environment remediation.

The implementation of carbon neutrality to achieve the goal of controlling global warming in the Paris Climate Agreement is currently the most important international climate issue. Efficient utilization of solar energy through photocatalysts is of great significance to the adjustment of energy structure. Single‐atom photocatalysts have excellent catalytic activity and selectivity in a variety of applications, including sustainable energy conversion, chemical synthesis, CO2 reduction, environmental remediation, and other areas, owing to their unique electronic structure and high atom usage. Here, we elaborated on the content and implementation direction of the carbon neutrality policy and demonstrated the design principles of single‐atom photocatalysts. Recent single‐atom synthesis strategies are summarized, and representative characterization methods have been shown to further reveal the structure–performance relationship. Then, we focus on the application of single‐atom photocatalysts in CO2 reduction, sustainable energy conversion, and environmental remediation. Finally, the opportunities and challenges in the application of single‐atom photocatalysts were discussed based on its current development.