Copper Nanowires: A Substitute for Noble Metals to Enhance Photocatalytic H₂ Generation

Microwave-assisted hydrothermal approach was developed as a general strategy to decorate copper nanowires (CuNWs) with nanorods (NRs) or nanoparticles (NPs) of metal oxides, metal sulfides, and metal organic frameworks (MOFs). The microwave irradiation induced local “super hot” dots generated on the CuNWs surface, which initiated the adsorption and chemical reactions of the metal ions, accompanied by the growth and assembly of NPs building blocks along the metal nanowires’ surfaces. This solution-processed approach enables the NRs (NPs) @CuNWs hybrid structure to exhibit three unique characteristics: (1) high coverage density of NRs (NPs) per NWs with the morphology of NRs (NPs) directly growing from the CuNWs core, (2) intimate contact between CuNWs and NRs (NPs), and (3) flexible choices of material composition. Such hybrid structures also increased light absorption by light scattering. In general, the TiO₂/CuNWs showed excellent photocatalytic activity for H₂ generation. The corresponding hydrogen production rate is 5104 μmol h^–1 g^–1 with an apparent quantum yield (AQY) of 17.2%, a remarkably high AQY among the noble-metal free TiO₂ photocatalysts. Such performance may be associated with the favorable geometry of the hybrid system, which is characterized by a large contact area between the photoactive materials (TiO₂) and the H₂ evolution cocatalyst (Cu), the fast and short diffusion paths of photogenerated electrons transferring from the TiO₂ to the CuNWs. This study not only shows a possibility for the utilization of low cost copper nanowires as a substitute for noble metals in enhanced solar photocatalytic H₂ generation but also exhibits a general strategy for fabricating other highly active H₂ production photocatalysts by a facile microwave-assisted solution approach

Pt-Enhanced Mesoporous Ti³⁺/TiO₂ with Rapid Bulk to Surface Electron Transfer for Photocatalytic Hydrogen Evolution

Pt-doped mesoporous Ti³⁺ self-doped TiO₂ (Pt–Ti³⁺/TiO₂) is <i>in situ</i> synthesized via an ionothermal route, by treating metallic Ti in an ionic liquid containing LiOAc, HOAc, and a H₂PtCl₆ aqueous solution under mild ionothermal conditions. Such Ti³⁺-enriched environment, as well as oxygen vacancies, is proven to be effective for allowing the <i>in situ</i> reduction of Pt⁴⁺ ions uniformly located in the framework of the TiO₂ bulk. The photocatalytic H₂ evolution of Pt–Ti³⁺/TiO₂ is significantly higher than that of the photoreduced Pt loaded on the original TiO₂ and commercial P25. Such greatly enhanced activity is due to the various valence states of Pt (Pt^<i>n</i>+, <i>n</i> = 0, 2, or 3), forming Pt–O bonds embedded in the framework of TiO₂ and ultrafine Pt metal nanoparticles on the surface of TiO₂. Such Pt^<i>n</i>+–O bonds could act as the bridges for facilitating the photogenerated electron transfer from the bulk to the surface of TiO₂ with a higher electron carrier density (3.11 × 10²⁰ cm^–3), about 2.5 times that (1.25 × 10²⁰ cm^–3) of the photoreduced Pt–Ti³⁺/TiO₂ sample. Thus, more photogenerated electrons could reach the Pt metal for reducing protons to H₂

Photocatalytic fuel cell – A review

Photocatalytic oxidation has been widely investigated and applied to perform degradation of organic pollutants in water and air. In recent technological advancement, photocatalysis (PC) is integrated into fuel cell (FC) to form photocatalytic fuel cell (PFC) for simultaneous wastewater treatment and production of electricity. In the PFC mechanisms, the organic pollutant, acting as a fuel in the fuel cell component, is decomposed upon light activation at the photoanode and the flow of photoexcited electrons is driven by the potential difference between the two electrodes. Thus, unwanted electron-hole recombination is effectively inhibited, resulting in enhanced PC activity. In other words, the chemical energy stored in the organic pollutant is recovered and converted into useful electricity during the wastewater treatment process. The photoelectrochemical technology can also be implemented for hydrogen generation and carbon dioxide reduction. Various strategies have been investigated for improving the PFC mechanisms through better visible-light photoelectrodes, innovative cell designs, dual-photoelectrode setup, as well as optimal control. In this review, the fundamentals and technological development of PFC will be discussed with special attention to novel cell configurations. With better knowledge and understanding of the PFC, we can identify promising research directions to further develop the PFC technologies

C₆₀-Decorated CdS/TiO₂ Mesoporous Architectures with Enhanced Photostability and Photocatalytic Activity for H₂ Evolution

Fullerene (C₆₀) enhanced mesoporous CdS/TiO₂ architectures were fabricated by an evaporation induced self-assembly route together with an ion-exchanged method. C₆₀ clusters were incorporated into the pore wall of mesoporous CdS/TiO₂ with the formation of C₆₀ enhanced CdS/TiO₂ hybrid architectures, for achieving the enhanced photostability and photocatalytic activity in H₂ evolution under visible-light irradiation. Such greatly enhanced photocatalytic performance and photostability could be due to the strong combination and heterojunctions between C₆₀ and CdS/TiO₂. The as-formed C₆₀ cluster protection layers in the CdS/TiO₂ framework not only improve the light absorption capability, but also greatly accelerated the photogenerated electron transfer to C₆₀ clusters for H₂ evolution

Solvent-Free Methallylboration of Ketones Accelerated by <i>tert</i>-Alcohols

A solvent- and metal-free process has been developed for the direct methallylboration of ketones employing the stable <i>B</i>-methallylborinane <b>1</b>, which was accelerated by tertiary alcohols. In the presence of 2.0 equiv of readily available tertiary alcohols such as <i>tert</i>-amyl alcohol, the methallylation products were prepared at room temperature in excellent yields. The salient features of the described process include simple operation, high efficiency, and mild reaction conditions

S‑Scheme Photocatalyst NH₂–UiO-66/CuZnS with Enhanced Photothermal-Assisted CO₂ Reduction Performances

Green and mild sunlight-driven photocatalysis has emerged as a promising technology for mitigating climate- and energy-related issues. In CO2 reduction reactions, metal–organic framework (MOF) materials are often compounded with inorganic semiconductor ZnS to form S-scheme photocatalysts that facilitate effective charge migration and separation across the composite interface. However, the large bandwidth of unmodified or modified ZnS remains a major hurdle in achieving efficient photocatalytic reactions. Therefore, this study aimed to reduce the band gap width of ZnS by incorporating Cu-doped ZnS(en)0.5 (CuZnS) as the inorganic semiconductor substrate and NH2–UiO-66 as the organometallic framework material to prepare NH2–UiO-66/CuZnS composite photocatalysts, ultimately realizing a thermally assisted photocatalytic CO2 reduction reaction. With the help of photothermal conversion from CuZnS, the temperature of CO2 reduction increased to 54.2 °C, resulting in a fast kinetic showing an improved yield of 22.85 μmol g–1 h–1 via the photocatalytic route

One-Pot and Regiospecific Synthesis of 2,3-Disubstituted Indoles from 2‑Bromoanilides via Consecutive Palladium-Catalyzed Sonogashira Coupling, Amidopalladation, and Reductive Elimination

A practical one-pot and regiospecific three-component process for the synthesis of 2,3-disubstituted indoles from 2-bromoanilides was developed via consecutive palladium-catalyzed Sonogashira coupling, amidopalladation, and reductive elimination

Asymmetric Synthesis of Sulfinamides Using (−)-Quinine as Chiral Auxiliary

A process has been designed and demonstrated for the asymmetric synthesis of sulfinamides using quinine as auxiliary. A variety of chiral sulfinamides including <i>N</i>-alkyl sulfinamides with diverse structure were prepared in good yields and excellent enantioselectivity starting from easily available and inexpensive reagents. The auxiliary quinine could be recovered and recycled

Carbamoyl Anion Addition to <i>N</i>‑Sulfinyl Imines: Highly Diastereoselective Synthesis of α‑Amino Amides

Carbamoyl anions, generated from N,N-disubstituted formamides and lithium diisopropylamide, add with high diastereoselectivity to chiral <i>N</i>-sulfinyl aldimines and ketimines to provide α-amino amides. The methodology enables the direct introduction of a carbonyl group without the requirement of unmasking steps as with other nucleophiles. The products may be converted to α-amino esters or 1,2-diamines. Iterative application of the reaction enabled the stereoselective synthesis of a dipeptide. Spectroscopic and computational studies support an anion structure with η² coordination of lithium by the carbonyl group