ABSTRACT
Photocatalytic degradation of organic pollutants in water is of great significance to the sustainable development of the environment, but encounters limited efficiency when a single compound is used. Thus, there have been enormous efforts to find novel photocatalytic heterostructured composites with high performance. In this work, a novel S-scheme heterostructure is constructed with BiOBr and Zn2+ doped C4N3 (Zn-C4N3) by a solvothermal method for efficient photodegradation of tetracycline (TC), a residual antibiotic difficult to be removed from the aquatic environment. Thanks to Zn2+-doping induced improvement in chemical affinity between Zn-C4N3 and BiOBr, well-formed Zn-C4N3/BiOBr heterostructured hollow spheres are formed. This structure can efficiently suppress fast recombination of photogenerated electron-hole pairs to enhance the photocatalytic activity of BiOBr dramatically. At a room temperature of 25 °C and neutral pH 7, the catalyst can degrade a significant portion of TC pollutants within 30 min under visible light. Also, the Zn-C4N3/BiOBr heterostructure displays good stability after recycling experiments. Free radical capture experiments and ESR tests show that ËO2- is the main active substance for photocatalytic degradation of TC. This study provides new insights for constructing heterostructures with an intimate interface between the two phases for photocatalytic applications.
ABSTRACT
The oxygen evolution reaction (OER) has garnered considerable attention because of its promising prospects in electrochemical energy conversion applications, but a significant challenge is faced by the insufficient understanding of sluggish OER kinetics. In fact, the intrinsic "acceptance-donation" process of electrons between active sites and reactants is responsible for improving OER activity. Herein, we suggest a multielement hybridization strategy to rematch spin electron occupation and energy splitting in high-entropy perovskites with multiple orbital coordination. In this concept, electronic hopping between t2g and eg orbitals among particular catalytic sites can be obviously enforced due to introducing more favorable energy levels from neighboring metal sites, which can demonstrate multistage orbital hybridization reaction activity. As a result, our proposed multistage-hybridized high-entropy perovskites display an impressive activity of 199.8 mA cm-2 as an overpotential of â¼0.46 V, which is â¼5.3 times that of pristine perovskite. Different from traditional catalyst designs, this study focuses on multistage orbital hybridization and electron exchange interactions through a multisite coordination mechanism to construct a fast reaction pathway. Our findings provide a new strategy for accelerating OER catalytic kinetics.
ABSTRACT
This work suggests an intriguing light-driven atomic assembly proposal to orderly configure the distribution of reactive sites to optimize the spin-entropy-related orbital interaction and charge transfer from electrocatalysts to intermediates. Herein, the introduced fluorine (F) atoms acting as photo-corrosion centres in MnO1.9 F0.1 effectively soften the bonding interaction of Mn-O bonds in the IrCl3 solution. Therefore, partial Mn atoms can be successively replaced to form orderly atomic-hybridized catalysts with a spin-related low entropy due to the coexistence of Ir-atomic chains and clusters. The time-related elemental analysis demonstrates that the dynamic dissolution/redeposition of Ir clusters in acidic oxygen evolution leads to a reintegration of the reaction pathway to seek the switchable rate-limiting step with a lower activation energy.
ABSTRACT
The exploitation of stable and earth-abundant photocatalysts with high catalytic activity remains a significant challenge for removing heavy metals from wastewater. Different from complex nanostructuring, this work focuses on a simple and feasible way to design catalysts. Herein, MoO3 nanosheets were fabricated and grown vertically on the surface of a quartz tablet using a one-step chemical vapor deposition method. The morphology, construction and optical properties of the MoO3 were characterized by XRD, XPS, SEM, HRTEM and UV-Vis methods, and the possible growth mechanism was also discussed. It can be found that the MoO3 nanosheets exhibited significantly enhanced visible light photocatalytic reduction capacity with stable recyclability to Cr(vi). The results show that the MoO3 nanosheets can be used as a cost-effective and recyclable photocatalyst for the removal of Cr(vi) from water. Our findings provide new inspiration for the design of new types of catalysts.
