Nanostructured manganese oxide on fullerene soot for water oxidation under neutral conditions

The sluggish kinetics of oxygen-evolution reaction (OER) through water-oxidation reaction results in high overpotentials for water splitting. Among different compounds, carbon-based material/Mn oxide composites were reported as OER catalysts. Fullerene soot (FS), which contains a mixture of fullerenes and carbon blacks, is low-cost compared to fullerenes and is commercially available. Herein, the Mn oxide/fullerene soot (MnO_x/FS) composite was investigated as an OER catalyst under neutral conditions. The composite was prepared through the reaction of KMnO₄ and FS as a facile, easy, and low-cost procedure. In this method, amorphous Mn oxide is formed directly on FS. The material was characterized by a number of methods. Then, the OER catalytic activity of MnO_x/FS was studied in a LiClO₄ solution (pH ≈ 6.3). Compared to pristine FS, the OER activity of MnO_x/FS is 2.5 times higher at 2.25 V vs. RHE. The Tafel slopes for OER are 450 and 240 mV per decade for FS and the reported composite, respectively.     

UV-light-assisted synthesis of CeB6@Ag nano-trees for SERS application

The conventional methods of using surfactants to synthesize noble metal nanoparticles usually introduce residues on the surface,which inevitably decreases nanoparticles’ surface enhanced Raman scattering(SERS) performance.Herein,we propose a surfactant-free and feasible approach of preparing cerium hexaboride-Ag nano-trees hybrids(CeB₆@Ag nano-trees) as the SERS substrate.First,the CeB₆ was synthesized by a one-pot ionothermal method.Secondly,the CeB₆ powder and ...     

Photosynthesis of Hydrogen Peroxide Based on g‑C3N4: The Road of a Cost-Effective Clean Fuel Production

Emerging artificial photosynthesis promises to offer a competitive means for solar energy conversion and further solves the energy crisis facing the world. Hydrogen peroxide (H₂O₂), which is considered as a benign oxidant and a prospective liquid fuel, has received worldwide attention in the field of artificial photosynthesis on account of the source materials are just oxygen, water, and sunlight. Graphitic carbon nitride (g-C₃N₄)-based photocatalysts for H₂O₂ generation have attracted extensive research interest due to the intrinsic properties of g-C₃N₄. In this review, research processes for H₂O₂ generation on the basis of g-C₃N₄, including development, fabrication, merits, and disadvantages, and the state-of-the-art methods to enhance the performance are summarized after a brief introduction and the mechanism analysis of an efficient catalytic system. Also, recent applications of g-C₃N₄-based photocatalysts for H₂O₂ production are reviewed, and the significance of active sites and synthetic pathways are highlighted from the view of reducing barriers. Finally, this paper ends with some concluding remarks to reveal the issues and opportunities of g-C₃N₄-based photocatalysts for producing H₂O₂ in a high yield.     

Pyridinic Nitrogen Doped Carbon Dots Supply Electrons to Improve Photosynthesis and Extracellular Electron Transfer of Chlorella pyrenoidosa

Optimizing photosynthesis is imperative for providing energy and organics for all life on the earth. Here, carbon dots doped with pyridinic nitrogen (named lev-CDs) are synthesized by the one-pot hydrothermal method, and the structure–function relationship between functional groups on lev-CDs and photosynthesis of Chlorella pyrenoidosa (C. pyrenoidosa) is proposed. Pyridinic nitrogen plays a key role in the positive effect on photosynthesis caused by lev-CDs. In detail, lev-CDs act as electron donors to supply photo-induced electrons to P680⁺ and QA⁺, causing electron transfer from lev-CDs to the photosynthetic electron transport chain in the photosystems. In return, the recombination efficiency of electron–hole pairs on lev-CDs decreases. As a result, the electron transfer rate in the electron transport chain, the activity of photosystem II, and the Calvin cycle are enhanced. Moreover, the electron transfer rate between C. pyrenoidosa and external circumstances enhanced by lev-CDs is about 50%, and electrons exported from C. pyrenoidosa can be used to reduce iron(III). This study is of great significance for engineering nanomaterials to improve photosynthesis.     

Loaded Cu-Er metal iso-atoms on graphdiyne for artificial photosynthesis

Herein we report a bimetal atomic catalyst that features atomically dispersed Cu and Er atoms anchored on all crystalline graphdiyne (CuEr-GDY) for efficient artificial photosynthesis converting CO₂ into sustainable fuel at the gas–solid interfaces with water as reducing medium instead of organic reagent. The CuEr-GDY can promote the efficient separation of photogenerated electron-hole pairs to drive water oxidation and CO₂ activation/reduction, together with Cu/Er promoted CO₂/H₂O adsorption and CO desorption. This result indicates that bimetallic atoms on the high-crystalline GDY surface have high activity. This heteroatomic catalyst of CuEr-GDY demonstrates high catalytic activity with the reaction selectivity up to 97.6%, and the competitive hydrogen evolution reaction is almost completely suppressed. The CO₂ conversion achieves the CO yield of 181.04 μmol g⁻¹ h⁻¹ under ambient conditions.