Two‐Dimensional Hollow TiO2 Nanoplates with Enhanced Photocatalytic Activity

Two‐dimensional anatase TiO₂ hollow nanoplates were firstly synthesized through a facile synthesis route by using α‐Fe₂O₃ nanoplates as removable templates. Two‐dimensional hollow TiO₂ nanoplates with different ratios of anatase and rutile phases were obtained by adjusting the calcining temperature. The average diameters were around 600 nm, and the shell thickness was approximately 30 nm. The photocatalytic performance of TiO₂ was investigated by decomposing rhodamine B under simulated sunlight. Among the TiO₂ samples, the anatase TiO₂ hollow nanoplates manifested a significant enhancement in the photocatalytic performances. The excellent catalytic performance can be attributed to the unique structure of the two‐dimensional anatase TiO₂ hollow nanoplates, including a large surface area and increased dye–photocatalyst contact areas as well as more active sites for photodegradation.     

Efficient Electrosynthesis of Syngas with Tunable CO/H2 Ratios over ZnxCd1−xS‐Amine Inorganic–Organic Hybrids

Efficient electrochemical reduction of CO₂ and H₂O into industrial syngas with tunable CO/H₂ ratios, especially integrated with anodic organic synthesis to replace the low‐value oxygen evolution reaction (OER), is highly desirable. Here, integration of controllable partial substitution of zinc (Zn) with amine incorporation into CdS‐amine inorganic‐organic hybrids is used to generate highly efficient electrocatalysts for synthesizing syngas with tunable CO/H₂ ratios (0–19.7), which are important feedstocks for the Fischer–Tropsch process. Diethylenetriamine could enhance the adsorption and accelerate the activation of CO₂ to form the key intermediate COOH* for CO formation. Zn substitution promoted the hydrogen evolution reaction (HER), leading to tunable CO/H₂ ratios. Importantly, syngas and dihydroisoquinoline can be simultaneously synthesized by pairing with anodic semi‐oxidation of tetrahydroisoquinoline in a Zn_xCd_1?xS‐Amine ∥ Ni₂P two‐electrode electrolyzer.     

Molten-Salt-Mediated Synthesis of an Atomic Nickel Co-catalyst on TiO2 for Improved Photocatalytic H2 Evolution

Atomic co-catalysts offer high potential to improve the photocatalytic performance, of which the preparation with earth-abundant elements is challenging. Here, a new molten salt method (MSM) is designed to prepare atomic Ni co-catalyst on widely studied TiO₂ nanoparticles. The liquid environment and space confinement effect of the molten salt leads to atomic dispersion of Ni ions on TiO₂, while the strong polarizing force provided by the molten salt promotes formation of strong Ni−O bonds. Interestingly, Ni atoms are found to facilitate the formation of oxygen vacancies (OV) on TiO₂ during the MSM process, which benefits the charge transfer and hydrogen evolution reaction. The synergy of atomic Ni co-catalyst and OV results in 4-time increase in H₂ evolution rate compared to that of the Ni co-catalyst on TiO₂ prepared by an impregnation method. This work provides a new strategy of controlling atomic co-catalyst together with defects for efficient photocatalytic water splitting.     

Constructing SrTiO3–TiO2 Heterogeneous Hollow Multi‐shelled Structures for Enhanced Solar Water Splitting

Constructing hollow multi‐shelled structures (HoMSs) has a significant effect on promoting light absorption property of catalysts and enhancing their performance in solar energy conversion applications. A facile hydrothermal method is used to design the SrTiO₃?TiO₂ heterogeneous HoMSs by hydrothermal crystallization of SrTiO₃ on the surface of the TiO₂ HoMSs, which will realize a full coverage of SrTiO₃ on the TiO₂ surface and construct the SrTiO₃/TiO₂ junctions. The broccoli‐like SrTiO₃?TiO₂ heterogeneous HoMSs exhibited a fourfold higher overall water splitting performance of 10.6 μmol h^?1 for H₂ production and 5.1 μmol h^?1 for O₂ evolution than that of SrTiO₃ nanoparticles and the apparent quantum efficiency (AQE) of 8.6 % at 365 nm, which can be mainly attributed to 1) HoMS increased the light absorption ability of the constructed photocatalysts and 2) the SrTiO₃?TiO₂ junctions boosted the separation efficiency of the photogenerated charge carriers.     

Vacancy‐Rich Monolayer BiO2−x as a Highly Efficient UV,Visible, and Near‐Infrared Responsive Photocatalyst

Vacancy‐rich layered materials with good electron‐transfer property are of great interest. Herein, a full‐spectrum responsive vacancy‐rich monolayer BiO_2−x has been synthesized. The increased density of states at the conduction band (CB) minimum in the monolayer BiO_2−x is responsible for the enhanced photon response and photo‐absorption, which were confirmed by UV/Vis‐NIR diffuse reflectance spectra (DRS) and photocurrent measurements. Compared to bulk BiO_2−x, monolayer BiO_2−x has exhibited enhanced photocatalytic performance for rhodamine B and phenol removal under UV, visible, and near‐infrared light (NIR) irradiation, which can be attributed to the vacancy V_Bi‐O′′′ as confirmed by the positron annihilation spectra. The presence of V_Bi‐O′′′ defects in monolayer BiO_2−x promoted the separation of electrons and holes. This finding provides an atomic level understanding for developing highly efficient UV, visible, and NIR light responsive photocatalysts.     

Indirect CO2 Methanation: Hydrogenolysis of Cyclic Carbonates Catalyzed by Ru‐Modified Zeolite Produces Methane and Diols

We report a ruthenium‐modified zeolite which efficiently transforms propylene carbonate to propylene glycol and methane, under solvent‐free conditions. The catalyst achieved high product selectivity and no significant ageing effect was observed after multiple cycles. The resulting liquid product (water‐containing glycol) can be directly used as anti‐freeze solution and the gas phase can directly be used as an energy carrier in the form of H₂‐enriched methane. This process efficiently bridges energy storage and an important chemical synthesis under sustainable (CO₂ consuming) conditions.     

Constructing Ordered Three‐Dimensional TiO2 Channels for Enhanced Visible‐Light Photocatalytic Performance in CO2 Conversion Induced by Au Nanoparticles

As a typical photocatalyst for CO₂ reduction, practical applications of TiO₂ still suffer from low photocatalytic efficiency and limited visible‐light absorption. Herein, a novel Au‐nanoparticle (NP)‐decorated ordered mesoporous TiO₂ (OMT) composite (OMT‐Au) was successfully fabricated, in which Au NPs were uniformly dispersed on the OMT. Due to the surface plasmon resonance (SPR) effect derived from the excited Au NPs, the TiO₂ shows high photocatalytic performance for CO₂ reduction under visible light. The ordered mesoporous TiO₂ exhibits superior material and structure, with a high surface area that offers more catalytically active sites. More importantly, the three‐dimensional transport channels ensure the smooth flow of gas molecules, highly efficient CO₂ adsorption, and the fast and steady transmission of hot electrons excited from the Au NPs, which lead to a further improvement in the photocatalytic performance. These results highlight the possibility of improving the photocatalysis for CO₂ reduction under visible light by constructing OMT‐based Au‐SPR‐induced photocatalysts.     

Bi‐, Y‐Codoped TiO2 for Carbon Dioxide Photocatalytic Reduction to Formic Acid under Visible Light Irradiation

Bi‐ and Y‐codoped TiO₂ photocatalysts were synthesized through a sol‐gel method, and they were applied in the photocatalytic reduction of CO₂ to formic acid under visible light irradiation. The results revealed that, after doping Bi and Y, the surface area of TiO₂ was increased from 5.4 to 93.1 m²/g when the mole fractions of doping Bi and Y were 1.0% and 0.5%, respectively, and the lattice structures of the photocatalysts changed and the oxygen vacancies on the surface of the photocatalysts formed, which would act as the electron capture centers and slow down the recombination of photo‐induced electron and hole. The photocurrent spectra also proved that the photocatalysts had better electronic transmission capacities. The HCOOH yield in CO₂ photocatalytic reduction was 747.82 μmol/g_cat by using 1% Bi‐0.5% Y‐TiO₂ as a photocatalyst. The HCOOH yield was 1.17 times higher than that by using 1% Bi‐TiO₂, and 2.23 times higher than that by using pure TiO₂. Furthermore, the 1% Bi‐0.5% Y‐TiO₂ showed the highest apparent quantum efficiency (AQE) of 4.45%.     

Hollow Multi‐Shelled Structural TiO2−x with Multiple Spatial Confinement for Long‐Life Lithium–Sulfur Batteries

TiO_2?x with well‐controlled hollow multi‐shelled structures (HoMSs) were designed and synthesized, via a sequential templating approach (STA), to act as sulfur carrier materials. They were explored as physico‐chemical encapsulation materials. Particularly, the sulfur cathode based on triple‐shelled TiO_2?x HoMSs delivered a specific capacity of 903 mAh g^?1 with a capacity retention of 79 % at 0.5 C and a Coulombic efficiency of 97.5 % over 1000 cycles. The outstanding electrochemical performance is attributed to better spatial confinement and integrated conductivity of the intact triple‐shell that combine the features of physico‐chemical adsorption, short charge transfer path along with mechanical strength.     

Controlled Supramolecular Self‐Assembly of Super‐charged β‐Lactoglobulin A–PEG Conjugates into Nanocapsules

The synthesis and characterization of a new protein–polymer conjugate composed of β lactoglobulin A (βLG A) and poly(ethylene glycol) PEG is described. βLG A was selectively modified to self‐assemble by super‐charging via amination or succinylation followed by conjugation with PEG. An equimolar mixture of the oppositely charged protein–polymer conjugates self‐assemble into spherical capsules of 80–100 nm in diameter. The self‐assembly proceeds by taking simultaneous advantage of the amphiphilicity and polyelectrolyte nature of the protein–polymer conjugate. These protein–polymer capsules or proteinosomes are reminiscent of protein capsids, and are capable of encapsulating solutes in their interior. We envisage this approach to be applicable to other globular proteins.     

2D Titania–Carbon Superlattices Vertically Encapsulated in 3D Hollow Carbon Nanospheres Embedded with 0D TiO2 Quantum Dots for Exceptional Sodium‐Ion Storage

Two‐dimensional (2D) superlattices offer promising technological opportunities in tuning the intercalation chemistry of metal ions. Now, well‐ordered 2D superlattices of monolayer titania and carbon with tunable interlayer‐spacing are synthesized by a molecularly mediated thermally induced approach. The 2D superlattices are vertically encapsulated in hollow carbon nanospheres, which are embedded with TiO₂ quantum dots, forming a 0D‐2D‐3D multi‐dimensional architecture. The multi‐dimensional architecture with the 2D superlattices encapsulated inside exhibits a near zero‐strain characteristic and enriched electrochemical reactivity, achieving a highly efficient Na⁺ storage performance with exceptional rate capability and superior long‐term cyclability.     

A Precious‐Metal‐Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO2‐to‐Syngas Conversion

Electrolyzers combining CO₂ reduction (CO₂R) with organic substrate oxidation can produce fuel and chemical feedstocks with a relatively low energy requirement when compared to systems that source electrons from water oxidation. Here, we report an anodic hybrid assembly based on a (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) electrocatalyst modified with a silatrane‐anchor ( STEMPO ), which is covalently immobilized on a mesoporous indium tin oxide (mesoITO) scaffold for efficient alcohol oxidation (AlcOx). This molecular anode was subsequently combined with a cathode consisting of a polymeric cobalt phthalocyanine on carbon nanotubes to construct a hybrid, precious‐metal‐free coupled AlcOx–CO₂R electrolyzer. After three‐hour electrolysis, glycerol is selectively oxidized to glyceraldehyde with a turnover number (TON) of ≈1000 and Faradaic efficiency (FE) of 83 %. The cathode generated a stoichiometric amount of syngas with a CO:H₂ ratio of 1.25±0.25 and an overall cobalt‐based TON of 894 with a FE of 82 %. This prototype device inspires the design and implementation of nonconventional strategies for coupling CO₂R to less energy demanding, and value‐added, oxidative chemistry.