Qingsheng Wu

Efficient photocatalytic nanocrystals with high-ratio exposure of active facets have aroused a great number of research interests in recent years. However, most preparations of such materials need the addition of special capping agents (like surfactants) or harsh reaction conditions (such as hydrothermal reactions). In this work, a controllable synthesis of BiOBr nanosheets with a thickness from 9 nm to 32 nm was easily achieved in a hydrolysis system through adjusting temperature and solvent, without adding any surfactant or capping agents. As the thickness of the nanosheets decreases from 32 nm to 9 nm, the ratio of exposed {001} facets, the active photocatalysis facets in BiOBr crystals, increases from 83% to 94%, along with an increased photocatalytic efficiency over rhodamine B (RhB) under visible-light. Various methods such as SEM, TEM, AFM, DRS and Raman spectroscopy were used to fully characterize the as-obtained BiOBr nanosheets. More importantly, the obtained BiOBr nanosheets exhibit a selective visible-light photocatalytic behavior as the activity over RhB is much higher than that over Methyl Orange (MO) or Methylene Blue (MB). This phenomenon was studied with in situ electron paramagnetic resonance (EPR) measurements and the potential mechanism was explored.

Abstract Supercapacitors are considered to be one of the most promising development directions of energy storage systems because of their low cost, environmental protection and high energy density. The performance of supercapacitors is determined with the quality of electrode materials. Co 3 O 4 , a kind of electrode material for supercapacitor, has attracted more and more attention in recent years due to its advantages of high theoretical capacity, low cost and natural abundance. In this review, the synthesis and electrochemical properties of Co 3 O 4 ‐based electrode materials are discussed in detail. Finally, the research and development prospect of Co 3 O 4 ‐based electrode materials have been discussed.

Abstract As a green and effective energy storage device, supercapacitors have been attractive due to their high power density along with long cycle stability. Among various electrode materials, carbon materials have drawn significant attention due to their wonderful properties, such as high specific surface area, electronic conductivity, chemical stability and porous structures. In addition, challenges come from global warming and environmental pollution, biomass derived carbon materials feature the concepts of the sustainable development of chemistry. In this, the review not only summarizes the most advanced progress in biomass derived heteroatoms self‐doped carbon materials for supercapacitor, but also provides important guidelines for the future design of biomass‐derived carbons with heteroatoms doping in specific energy applications.

Stepwise blossoming of nanoplate-assembled BiOBr microflowers from bud to blossom structures with average diameters from 1 to 3.5 μm and nanoplate thicknesses from 25 to 120 nm is obtained in a solvothermal system through surfactant modulation and time control. The above BiOBr structures exhibit excellent visible-light photocatalytic activity toward degradation of methylene blue (MB) solution, among which the structure from a 24 h reaction gives the best photocatalytic activity. A quantitative relationship is established among crystallite size (R), specific surface area (S) and photocatalytic activity (D). The equation D = 15(R)2/5(S)1/5 offers a quantitative characterization of crystallinity-dominated photocatalytic activity.

Nowadays, it is of great significance and a challenge to design a noble-metal-free catalyst with high activity and a long lifetime for the reduction of aromatic nitro-compounds. Here, a 2D structured nanocomposite catalyst with graphene supported CuNi alloy nanoparticles (NPs) is prepared, and is promising for meeting the requirements of green chemistry. In this graphene/CuNi nanocomposite, the ultra-small CuNi nanoparticles (∼2 nm) are evenly anchored on graphene sheets, which is not only a breakthrough in the structures, but also brings about an outstanding performance in activity and stability. Combined with a precise optimization of the alloy ratios, the reaction rate constant of graphene/Cu61Ni39 reached a high level of 0.13685 s(-1), with a desirable selectivity as high as 99% for various aromatic nitro-compounds. What's more, the catalyst exhibited a unprecedented long lifetime because it could be recycled over 25 times without obvious performance decay or even a morphology change. This work showed the promise and great potential of noble-metal-free catalysts in green chemistry.