Wurtzite CuGaS2 with an In-Situ-Formed CuO Layer Photocatalyzes CO2 Conversion to Ethylene with High Selectivity

Enhancing the Lewis acidity of single atom Tb via introduction of boron to achieve efficient photothermal synergistic CO2 cycloaddition

Nowadays, it is becoming increasingly urgent to lower the escalating carbon dioxide (CO2) to reduce greenhouse effect. Fortunately, it is an ideal strategy by using the inexhaustible solar energy as the driving force to manipulate the cycloaddition reaction, the atomic efficiency of which is 100 %. This work represents the first attempt on utilization of rare-earth metal Tb with atomic dispersion, and the structure of Tb coordinated with 4 N-atoms and 2B-atoms was constructed on interconnected carbon hollow spheres. The introduction of electron-deficient B reduces the electron density of Tb, thereby boosting Lewis acidity and promoting the occurrence of ring-opening reaction. The mechanism exploration enunciates that TbN4B2/C is a photothermal synergistic catalyst, the combined action of photogenerated electrons and strong Lewis acidic site of Tb reduces the free energy of the rate-determining step, and then improving the yield of cyclic carbonate up to 739 mmol g-1h-1.

Boosting Solar-Driven CO2 Conversion to Ethanol via Single-Atom Catalyst with Defected Low-Coordination Cu-N2 Motif

Cu-based catalysts have been shown to selectively catalyze CO2 photoreduction to C2+ solar fuels. However, they still suffer from poor activity and low selectivity. Herein, we report a high-performance carbon nitride supported Cu single-atom catalyst featuring defected low-coordination Cu-N2 motif (Cu-N2-V). Lead many recently reported photocatalysts and its Cu-N3 and Cu-N4 counterparts, Cu-N2-V exhibits superior photocatalytic activity for CO2 reduction to ethanol and delivers 69.8 μmol g-1 h-1 ethanol production rate, 97.8 % electron-based ethanol selectivity, and a yield of ~10 times higher than Cu-N3 and Cu-N4. Revealed by the extensive experimental investigation combined with DFT calculations, the superior photoactivity of Cu-N2-V stems from its defected Cu-N2 configuration, in which the Cu sites are electron enriched and enhance electron delocalization. Importantly, Cu in Cu-N2-V exist in both Cu+ and Cu2+ valence states, although predominantly as Cu+. The Cu+ sites support the CO2 activation, while the co-existence of Cu+/Cu2+ sites are highly conducive for strong *CO adsorption and subsequent *CO-*CO dimerization enabling C-C coupling. Furthermore, the hollow microstructure of the catalyst also promotes light adsorption and charge separation efficiency. Collectively, these make Cu-N2-V an effective and high-performance catalyst for the solar-driven CO2 conversion to ethanol. This study also elucidates the C-C coupling reaction path via *CO-*CO to *COCOH and rate-determining step, and reveals the valence state change of partial Cu species from Cu+ to Cu2+ in Cu-N2-V during CO2 photoreduction reaction.

Cascaded *CO-*COH Intermediates on a Nonmetallic Plasmonic Photocatalyst for CO2-to-C2H6 with 90.6 % Selectivity

Oxygen vacancies (OV) in nonmetallic plasmonic photocatalysts can decrease the energy barrier for CO2 reduction, boosting C1 intermediate production for potential C2 formation. However, their susceptibility to oxidation weakens C1 intermediate adsorption. Herein we proposed a "photoelectron injection" strategy to safeguard OV in W18O49 by creating a W18O49/ZIS (W/Z) plasmonic photocatalyst. Moreover, photoelectrons contribute to the local multi-electron environment of W18O49, enhancing the intrinsic excitation of its hot electrons with extended lifetimes, as confirmed by in situ XPS and femtosecond transient absorption analysis. Density functional theory calculations revealed that W/Z with OV enhances CO2 adsorption, activating *CO production, while reducing the energy barrier for *COH production (0.054 eV) and subsequent *CO-*COH coupling (0.574 eV). Successive hydrogenation revealed that the free energy for *CH2CH2 hydrogenation (0.108 eV) was lower than that for *CH2CH2 desorption for C2H4 production (0.277 eV), favouring C2H6 production. Consequently, W/Z achieves an efficient C2H6 activity of 653.6 μmol g-1 h-1 under visible light, with an exceptionally high selectivity of 90.6 %. This work offers a new strategy for the rational design of plasmonic photocatalysts with high selectivity for C2+ products.

Heterogeneous CuS QDs/BiVO4@Y2O2S Nanoreactor for Monitorable Photocatalysis

Exploration of multifunctional integrated catalysts is of great significance for photocatalysis toward practical application. Herein, a 1D confined nanoreactor with a heterogeneous core-shell structure is designed for synergies of efficient catalysis and temperature monitoring by custom encapsulation of Z-scheme heterojunction CuS quantum dots/BiVO4 (CuS QDs/BiVO4) and Y2O2S-Er, Yb. The dispersed active sites created by the QDs with high surface energy improve the mass transfer efficiency, and the efficient electron transport channels at the heterogeneous interface extend the carrier lifetime, which endows the nanoreactor with excellent catalytic performance. Meanwhile, real-time temperature monitoring is realized based on the thermally coupled levels 2H11/2/4S3/2→4I15/2 of Er3+ using fluorescence intensity ratio, which enables the monitorable photocatalysis. Furthermore, the nanoreactor with a multidimensional structure increases effective intermolecular collisions to facilitate the catalytic process by restricting the reaction within distinct enclosed spaces and circumvents potential unknown interaction effects. The design of multi-space nanoconfined reactors opens up a new avenue to modulate catalyst function, providing a unique perspective for photocatalytic applications in the mineralization of organic pollutants, hydrogen production, and nitrogen fixation.

Modulation of active center distance of hybrid perovskite for boosting photocatalytic reduction of carbon dioxide to ethylene

Solar-driven photocatalytic CO2 reduction is an energy-efficient and sustainable strategy to mitigate CO2 levels in the atmosphere. However, efficient and selective conversion of CO2 into multi-carbon products, like C2H4, remains a great challenge due to slow multi-electron-proton transfer and sluggish C-C coupling. Herein, a two-dimensional thin-layered hybrid perovskite is fabricated through filling of oxygen into iodine vacancy in pristine DMASnI3 (DMA = dimethylammonium). The rational-designed DMASnI3(O) induces shrinkage of active sites distance and facilitates dimerization of C-C coupling of intermediates. Upon simulated solar irradiation, the DMASnI3(O) photocatalyst achieves a high selectivity of 74.5%, corresponding to an impressive electron selectivity of 94.6%, for CO2 to C2H4 conversion and an effective C2H4 yield of 11.2 μmol g-1 h-1. In addition, the DMASnI3(O) inherits excellent water stability and implements long-term photocatalytic CO2 reduction to C2H4 in a water medium. This work establishes a unique paradigm to convert CO2 to C2+ hydrocarbons in a perovskite-based photocatalytic system.

Lattice Distortion in a Confined Structured ZnS/ZnO Heterojunction for Efficient Photocatalytic CO2 Reduction

It is a promising strategy to effectively promote "carbon neutrality" by reducing CO₂ to small energy molecules through photocatalysis technology. However, due to low light utilization and recombination of photogenerated carriers, photocatalysts usually have low activity and low selectivity for products. Herein, a hollow spherical ZnS/ZnO heterojunction with a spatial confinement effect photocatalyst was synthesized toward CO₂ photoreduction through preciously controlling the nano-/microstructure. The local lattice distortions were introduced into the surface of the hollow ZnS/ZnO microsphere, which activated lattice oxygen and provided additional active reaction sites. Furthermore, the heterojunction constructed between ZnS and ZnO interfaces facilitated the separation of photoinduced charge carriers. Combined with the natural advantage of enhanced light capture and absorption for a hollow confined structure, as a result, the systemic design in the electronic and confined structures for the photocatalyst has brought an excellent CO₂ reduction performance with a CO yield rate as high as 35.85 μmol g^-1h^-1 and durability under a 300 W Xe lamp irradiation without any sacrificial agent and cocatalyst.