Converting Organic Wastewater into CO Using MOFs-Derived Co/In2O3 Double-Shell Photocatalyst

Enhanced electrocatalytic nitrate-to-ammonia performance from Mott-Schottky design to induce electron redistribution

Constructing highly efficient electrocatalysts via interface manipulation and structural design to facilitate rapid electron transfer in electrocatalytic nitrate-to-ammonia conversion is crucial to attaining superior NH3 yield rates. Here, a Mott-Schottky type electrocatalyst of Co/In2O3 with a continuous fiber structure has been designed to boost the electrocatalytic nitrate-to-ammonia performance. The optimized Co/In2O3-1 catalyst exhibits an impressive NH3 yield rate of 70.1 mg cm-2 h-1 at -0.8 V vs. the reversible hydrogen electrode (RHE), along with an NH3 faradaic efficiency (FE) of 93.34% at 0 V vs. RHE, greatly outperforming the single-component Co and In2O3 samples. The yield rate of Co/In2O3-1 is also superior to that of most currently reported Co-based catalysts and heterostructured ones. Evidence from experiments and theoretical results confirms the formation of a Mott-Schottky heterojunction, which achieves a Co site enriched with electrons, coupled with an In2O3 facet enriched with holes, inducing an electron redistribution to promote the utilization of electroactive sites. Consequently, the reaction energy barrier for nitrate-to-ammonia conversion is significantly reduced, further enhancing its yield efficiency.

Comprehensive Insight into Indium Oxide‐Based Catalysts for CO2 Hydrogenation: Thermal, Photo, and Photothermal Catalysis

The conversion of carbon dioxide (CO2) into value‐added chemicals presents an innovative pathway for advancing the low‐carbon clean energy revolution, contributing significantly to CO2 emission reduction and resource utilization. Recently, In2O3‐based catalysts have emerged as a promising frontier in CO2 hydrogenation research. This review provides a comprehensive introduction of the latest advancements in the application of In2O3‐based catalysts across thermal, photocatalytic, and photothermal catalysis platforms. The review examines critical aspects such as structural properties, active sites, reaction mechanisms, performance enhancement, product impact, and the development of multi‐functional catalytic systems. Thermal Catalysis for CO2 hydrogenation involves the application of elevated temperatures to initiate and drive the hydrogenation reactions. Photocatalysis, on the other hand, harnesses light energy to facilitate these reactions. Among these approaches, photothermal catalysis has emerged as a particularly promising method for CO2 hydrogenation, offering several advantages over both thermal catalysis and photocatalysis. These advantages include more efficient energy utilization, a broader range of reaction conditions, enhanced synergistic effects, selective activation, and improved environmental sustainability. This review not only summarizes the current state of research in this field but also may provide critical insights and guidance for future studies aimed at advancing artificial carbon cycling processes.

Indium oxide-based Z-scheme hollow core-shell heterostructure with rich sulfur-vacancy for highly efficient light-driven splitting of water to produce clean energy

Crafting an inorganic semiconductor heterojunction with defect engineering and morphology modulation is a strategic approach to produce clean energy by the highly efficient light-driven splitting of water. In this paper, a novel Z-scheme sulfur-vacancy containing Zn3In2S6 (Vs-Zn3In2S6) nanosheets/In2O3 hollow hexagonal prisms heterostructrue (Vs-ZIS6INO) was firstly constructed by an oil bath method, in which Vs-Zn3In2S6 nanosheets grew on the surfaces of In2O3 hollow hexagonal prisms to form a hollow core-shell structure. The obtained Vs-ZIS6INO heterostructrue exhibited much enhanced activity of the production of H2 and H2O2 by the light-driven water splitting. In particular, under visible light irradiation (λ > 420 nm), the rate of generation of H2 of Vs-ZIS6INO sample containing 30 wt% Vs-Zn3In2S6 (30Vs-ZIS6INO) could reach 3721 μmol g-1h-1, which was 87 and 6 times higher than those of Zn3In2S6 (43 μmol g-1h-1) and Vs-Zn3In2S6 (586 μmol g-1h-1), respectively. Meanwhile, 30Vs-ZIS6INO could exhibit the rate of H2O2 production of 483 μmol g-1h-1 through the dual pathways of indirect 2e- oxygen reduction (ORR) and water oxidation (WOR) without adding any sacrifice agents, far exceeding In2O3 (7 μmol g-1h-1) and Vs-Zn3In2S6 (58 μmol g-1h-1). The excellent photocatalytic activities of H2 and H2O2 generations of Vs-ZIS6INO sample might result from the synergistic effect of the sulfur vacancy, hollow core-shell structure, and Z-scheme heterostructure, which accelerated the electron delocalization, enhanced the absorption and conversion of solar energy, reduced the carrier diffusion distance, and ensured high REDOX ability. In addition, the possible photocatalytic mechanisms for the production of H2 and H2O2 were discussed in detail. This study provided a new idea and reference for constructing the novel and efficient inorganic semiconductor heterostructures by coordinating vacancy defect and morphology design to adequately utilize water splitting for the production of clean energy.

Optimized silicate nanozymes with atomically incorporated iron and manganese for intratumoral coordination-enhanced once-for-all catalytic therapy

Although plant-derived cancer therapeutic products possess great promise in clinical translations, they still suffer from quick degradation and low targeting rates. Herein, based on the oxygen vacancy (OV)-immobilization strategy, an OV-enriched biodegradable silicate nanoplatform with atomically dispersed Fe/Mn active species and polyethylene glycol modification was innovated for loading gallic acid (GA) (noted as FMMPG) for intratumoral coordination-enhanced multicatalytic cancer therapy. The OV-enriched FMMPG nanozymes with a narrow band gap (1.74 eV) can be excited by a 650 nm laser to generate reactive oxygen species. Benefiting from the Mn-O bond in response to the tumor microenvironment (TME), the silicate skeleton in FMMPG collapses and completely degrades after 24 h. The degraded metal M (M = Fe, Mn) ions and released GA can in situ produce a stable M-GA nanocomplex at tumor sites. Importantly, the formed M-GA with strong reductive ability can transform H2O2 into the fatal hydroxyl radical, causing serious oxidative damage to the tumor. The released Fe3+ and Mn2+ can serve as enhanced contrast agents for magnetic resonance imaging, which can track the chemodynamic and photodynamic therapy processes. The work offers a reasonable strategy for a TME-responsive degradation and intratumoral coordination-enhanced multicatalytic therapy founded on bimetallic silicate nanozymes to achieve desirable tumor theranostic outcomes.

Pd/Pt-Bimetallic-Nanoparticle-Doped In2O3 Hollow Microspheres for Rapid and Sensitive H2S Sensing at Low Temperature

H₂S is a poisonous gas that is widespread in nature and human activities. Its rapid and sensitive detection is essential to prevent it from damaging health. Herein, we report Pd- and Pt-bimetallic-nanoparticle-doped In₂O₃ hollow microspheres that are synthesized using solvothermal and in situ reduction methods for H₂S detection. The structure of as-synthesized 1 at% Pd/Pt-In₂O₃ comprises porous hollow microspheres assembled from In₂O₃ nanosheets with Pd and Pt bimetallic nanoparticles loaded on its surface. The response of 1 at% Pd/Pt-In₂O₃ to 5 ppm H₂S is 140 (70 times that of pure In₂O₃), and the response time is 3 s at a low temperature of 50 °C. In addition, it can detect trace H₂S (as low as 50 ppb) and has superior selectivity and an excellent anti-interference ability. These outstanding gas-sensing performances of 1 at% Pd/Pt-In₂O₃ are attributed to the chemical sensitization of Pt, the electronic sensitization of Pd, and the synergistic effect between them. This work supplements the research of In₂O₃-based H₂S sensors and proves that Pd- and Pt-bimetallic-doped In₂O₃ can be applied in the detection of H₂S.

In Situ Self-Assembled ZIF-67/MIL-125-Derived Co3O4/TiO2 p-n Heterojunctions for Enhanced Photocatalytic CO2 Reduction

Photocatalytic CO₂ reduction to carbon fuels is regarded as an ideal and sustainable way to provide clean energy and solve environmental crisis. Herein, a p-n Co₃O₄/TiO₂ heterojunction photocatalyst was synthesized by one-step pyrolysis of self-assembly ZIF-67/MIL-125, which was used in photocatalytic CO₂ reduction for the first time. Co₃O₄ nanocages were highly dispersed on the surface of TiO₂ nanoplates with an intimate contact. The optimal Co₃O₄/TiO₂ exhibited a significantly enhanced CO evolution rate of 1256 μmol g^-1 h^-1 under simulated solar light, which was 2.4 times higher than that of pure Co₃O₄. The high photocatalytic performance of Co₃O₄/TiO₂ was attributed to its enriched active sites and formed p-n heterojunctions. According to the electrocatalytic measurements, the possible mechanism and photoinduced charge transfer process were discussed in detail. We believe that this research provides a facile and efficient approach to fabricate MOF-derived heterojunction photocatalysts for CO₂ reduction.