Constructing photocatalysts decorated with atomically dispersed metal species (ADMs) represents a pivotal strategy to maximize atom utilization and tailor active sites for efficient carbon dioxide (CO₂) reduction. However, conventional synthesis strategies, typically relying on tedious wet-chemistry or prolonged thermal calcination, often suffer from slow kinetics that inevitably drive the thermodynamic aggregation of metastable single atoms or nanoclusters into less active nanoparticles. Herein, we bypass these limitations by developing a facile flash Joule heating (FJH) strategy to engineer stable Cu ADMs on TiO₂ via an ultrafast, millisecond-scale heating-quenching process. This non-equilibrium thermal shock effectively stabilizes the metal species before thermal diffusion can occur, ensuring a robust metal-support interaction as unambiguously confirmed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) analysis. Consequently, the optimized Cu_1.0/TiO₂ delivers an approximately 10-fold enhancement in CO evolution compared to pristine TiO₂ under simulated solar irradiation. Comprehensive in-situ diffuse reflectance Fourier transform spectroscopy (DRIFTS) and photoelectrochemical measurements reveal that these isolated Cu sites function as superior electron-trapping centers, which significantly accelerate interfacial charge transfer kinetics and promote the activation of critical reaction intermediates. This work establishes FJH as a versatile and scalable platform for overcoming the stability-dispersion trade-off in the rational design of high-performance photocatalysts.

Vacancy defect engineering represents one of the most effective strategies for enhancing photocatalytic performance. However, the wide applications of vacancy defect engineering are confronted with the problems of lack of precise control over vacancy defect engineering and poor stability. Herein, we employed an advanced pulse laser ablation in liquid (PLAL) method to introduce sulfur vacancies on the ZnIn₂S₄ nanosheets. Specifically, the vacancy concentration on the ZnIn₂S₄ can be easily modulated by changing the time for PLAL. In addition, it is discovered that the introduction of sulfur vacancies on the ZnIn₂S₄ nanosheets can provide enormous surface-active sites and facilitate the photogenerated charge carrier, thereby enhancing the photocatalytic CO₂ conversion. Compared to the pristine ZnIn₂S₄, the sulfur vacancies-rich ZnIn₂S₄ nanosheets show 15-fold enhancement in photocatalytic CO₂ conversion performance towards CO production, reaching 365 µmol·g⁻¹·h⁻¹. In addition, the sulfur vacancy-rich ZnIn₂S₄ shows a high stability for photocatalytic CO₂ conversion, retaining its performance after 12 h of reaction. According to the mechanistic studies, it is revealed that the sulfur vacancies can also enhance the adsorption capability of ZnIn₂S₄, thereby reducing the potential barrier for subsequent conversion. This work demonstrates the potential of the PLAL strategy for not only precisely introducing vacancy defects on the semiconductors, but also enhancing the stability of the defects, which can pave new avenues for the photocatalytic applications.

The photocatalytic ultrafiltration membranes have been demonstrated to be efficient for the treatment of various wastewaters under mild conditions at low cost, but it remains challenging to maintain their high efficiency due to irreversible membrane fouling, low mass transfer efficiency in the photocatalyst layer, and low stability of the membrane to ultraviolet (UV) radiation. To this end, negatively-charged amphiphilic polyvinylidene fluoride (PVDF) ultrafiltration membranes were prepared, and polyoxotitanium clusters (PTCs) with broad visible light response were incorporated into them to develop a self-cleaning membrane. High resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and corresponding energy dispersive X-ray spectrometry (EDS) verify that the sub-nanometer PTCs are uniformly implanted into the membrane pore. The hydraulic test shows that the pores are not blocked by the implanted photocatalysts. The optimized composite photocatalytic membrane (PM3) benefits from the electrostatic enrichment of the basement membrane and the efficient mass transfer in a nanoscale confined channel. This allows the membrane to self-clean by degrading dyes under visible light irradiation. Compared with the original membrane, PM3 could maintain high permeate flux and dye rejection rate with negative fouling ratio during 5 cycles. This design enabled efficient removal of Rhodamine B (RhB, > 85%) during 200 min of continuous separation, whereas it could only maintain less than 50 min on the original membrane. This work provides a common and facile process to develop photocatalytic ultrafiltration membranes with catalysts confined in nanoscale channels for efficient wastewater treatment.

The electrochemical conversion of CO₂ to C₂₊ products represents a significant technological opportunity for addressing global climate change. Nevertheless, copper-based catalysts continue to present challenges in terms of selectivity and the long-term stability of C₂₊ products. In this study, we demonstrate that the introduction of a second metal, silver (Ag), onto copper-based catalysts represents an effective strategy for enhancing the selectivity and reactivity of these catalysts in the electrochemical CO₂ reduction reaction. This approach involves modulating the adsorption strength or geometry of CO intermediates on the Cu-based catalyst surface. The results demonstrate that the Faradaic efficiency (FE) of C₂₊ products in the electrochemical CO₂ reduction reaction over a 5% Ag/Cu catalyst is 77%–80% within the current density range of 800 to 1000 mA·cm⁻². Furthermore, stability tests were conducted on the electrochemical CO₂ reduction reaction in a membrane electrolyzer using pure water as the electrolyte. Following a 15 h testing period at a current of −1000 mA, the FE of CO₂ reduction was observed to be 45%, indicating favorable stability. This provides a foundation for further research and development in the industrial application of electrochemical CO₂ reduction.

The thermodynamically favorable electrocatalytic oxidation coupled with hydrogen evolution reaction (HER) is considered as a sustainable and promising technique. Nonetheless, it remains a great challenge due to the lack of simple, cheap, and high-efficient electrocatalysts. Here, we successfully develop a simple and scalable electro-deposition and subsequent phosphorization route to fabricate Ni-doped Co₂P (Ni-Co₂P) nanosheets catalyst using the in-situ released Ni species from defective Ni foam as metal source. Impressively, the as-synthesized Ni-Co₂P catalyst exhibits excellent electrochemical 5-hydroxymethylfurfural oxidation reaction (HOR) performance with > 99% 2,5-furandicarboxylic acid yield and > 97% Faradaic efficiency at an ultralow potential of 1.29 V vs. reversible hydrogen electrode (RHE). Experimental characterization and theoretical calculation reveal that the atomically doped Ni species can enhance the adsorption of reactant and thus lower the reaction energy barriers. By coupling the electrocatalytic HOR with HER, the employed two-electrode system using Ni-Co₂P and commercial Ni foam as anode and cathode, respectively, exhibits a low cell voltage of 1.53 V to drive a current density of 10 mA·cm⁻², which is 90 mV lower than that of pure water splitting. This work provides a facile and efficient approach for the preparation of high-performance earth-abundant electrocatalysts toward the concurrent production of H₂ and value-added chemicals.

Sodium-ion batteries (SIBs) are considered the most up-and-coming complements for large-scale energy storage devices due to the abundance and cheap sodium. However, due to the bigger radius, it is still a great challenge to develop anode materials with suitable space for the intercalation of sodium ions. Herein, we present hard carbon microtubes (HCTs) with tunable apertures derived from low-cost natural kapok fibers via a carbonization process for SIBs. The resulted HCTs feature with smaller surface area and shorter Na⁺ diffusion path benefitting from their unique micro-nano structure. Most importantly, the wall thickness of HCTs could be regulated and controlled by the carbonization temperature. At a high temperature of 1,600 °C, the carbonized HCTs possess the smallest wall thickness, which reduces the diffusion barrier of Na⁺ and enhances the reversibility Na⁺ storage. As a result, the 1600HCTs deliver a high initial Coulombic efficiency of 90%, good cycling stability (89.4% of capacity retention over 100 cycles at 100 mA·g⁻¹), and excellent rate capacity. This work not only charts a new path for preparing hard carbon materials with adequate ion channels and novel tubular micro-nano structures but also unravels the mechanism of hard carbon materials for sodium storage.

Organic synthesis driven by heterogeneous catalysis is a central research theme to both fundamental research and industrial production of fine chemicals. However, the employment of stoichiometric strong oxidizing or reducing reagents (e.g., K₂Cr₂O₇ and LiAlH₄) and harsh reaction conditions (e.g., high temperature and pressure) always leads to the products of overreaction and other by-product residues (e.g., salt and acid waste). Thus the poor control of product selectivity and tremendous energy consumption result in the urgent demand to develop novel technologies for heterogeneous catalysis. Given the current global theme of development in CO₂ reduction and sustainable energy utilization, one promising protocol is heterogeneous photocatalysis. It enables sustainable solar-to-chemical energy conversion under mild conditions (e.g., room temperature, ambient pressure, and air as the oxidant) and offers unique reaction pathways for improved selectivity control. To accurately tailor the selectivity of desired products, the electronic structure (e.g., positions of valence-band maximum and conduction-band minimum), geometric structure (e.g., nanorod, nanosheet, and porous morphology), and surface chemical micro-environment (e.g., vacancy sites and co-catalysts) of heterogeneous photocatalysts require rational design and construction. In this review, we will briefly analyze some effective photocatalytic systems with the excellent regulation ability of product selectivity in organic transformations (mainly oxidation and reduction types) under visible light irradiation, and put forward opinions on the optimal fabrication of nanostructured photocatalysts to realize selective organic synthesis.

Synergistically combining biological whole-cell bacteria with man-made semiconductor materials innovates the way for sustainable solar-driven CO₂ fixation, showing great promise to break through the bottleneck in traditional chemical photocatalyst systems. However, most of the biohybrids require uneconomical organic nutrients and anaerobic conditions for the successful cultivation of the bacteria to sustain the CO₂ fixation, which severely limits their economic viability and applicability for practical application. Herein, we present an inorganic-biological hybrid system composed of obligate autotrophic bacteria Thiobacillus thioparus (T. thioparus) and CdS nanoparticles (NPs) biologically precipitated on the bacterial surface, which can achieve efficient CO₂ fixation based entirely on cost-effective inorganic salts and without the restriction of anaerobic conditions. The optimized interface between CdS NPs and T. thioparus formed by biological precipitation plays an essential role for T. thioparus efficiently receiving photogenerated electrons from CdS NPs and thus changing the autotrophic way from chemoautotroph to photoautotroph. As a result, the CdS–T. thioparus biohybrid realizes the solar-driven CO₂ fixation to produce multi-carbon glutamate synthase and biomass under visible-light irradiation with CO₂ as the only carbon source. This work provides significant inspiration for the further exploration of the solar-driven self-replicating biocatalytic system to achieve CO₂ fixation and conversion.

Replacement of enzymes with nanomaterials such as atomically dispersed metal catalysts is one of the most crucial steps in addressing the challenges in biocatalysis. Despite the breakthroughs of single-atom catalysts in enzyme-mimicking, a fundamental investigation on the development of an instructional strategy is still required for mimicking biatomic/multiatomic active sites in natural enzymes and constructing synergistically enhanced metal atom active sites. Herein, Fe₂NC catalysts with atomically dispersed Fe-Fe dual-sites supported by the metal-organic frameworks-derived nitrogen-doped carbon are employed as biomimetic catalysts to perform proof-of-concept investigation. The effect of Fe atom number toward typical oxidase (cytochrome C oxidase, NADH oxidase, and ascorbic acid oxidase) and peroxidase (NADH peroxidase and ascorbic acid peroxidase) activities is systematically evaluated by experimental and theoretical investigations. A peroxo-like O₂ adsorption in Fe₂NC nanozymes could accelerate the O–O activation and thus achieve the enhanced enzyme-like activities. This work achieves the vivid simulation of the enzyme active sites and provides the theoretical basis for the design of high-performance nanozymes. As a concept application, a colorimetric biosensor for the detection of S^2– in tap water is established based on the inhibition of enzyme-like activity of Fe₂NC nanozymes.

Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide (CO₂) conversion into multi-carbon hydrocarbons. However, during the electrochemical reaction, Cu catalysts inevitably undergo surface reconstruction whose impact on CO₂ conversion performance remains contentious. Here we report that polycrystalline Cu nanoparticles (denoted as Cu-s) with rich high-index facets, derived from Cu_2−xS through desulphurization and surface reconstruction, offer an excellent platform for investigating the role of surface reconstruction in electrocatalytic CO₂ conversion. During the formation of Cu-s catalyst, the two stages of desulphurization and surface reconstruction can be clearly resolved by in situ X-ray absorption spectroscopy and OH⁻ adsorption characterizations, which are well correlated with the changes in electrocatalytic performance. It turns out that the high CO₂ conversion performance, achieved by the Cu-s catalyst (Faradic efficiency of 68.6% and partial current density of 40.8 mA/cm² in H-cell toward C₂H₄ production), is attributed to the increased percentage of high-index facets in Cu-s during the surface reconstruction. Furthermore, the operando electrochemical Raman spectroscopy further reveals that the conversion of the CO₂ into the C₂H₄ on Cu-s is intermediated by the production of *COCHO. Our findings manifest that the surface reconstruction is an effective method for tuning the reaction intermediate of the CO₂ conversion toward high-value multicarbon (C₂₊) chemicals, and highlight the significance of in situ characterizations in enhancing the understanding of the surface structure and its role in electrocatalysis.