Hong-Yan Chen

Bio: Hong-Yan Chen is an academic researcher from Sun Yat-sen University. The author has contributed to research in topics: Dye-sensitized solar cell & Perovskite (structure). The author has an hindex of 37, co-authored 65 publications receiving 4760 citations.

A CsPbBr3 Perovskite Quantum Dot/Graphene Oxide Composite for Photocatalytic CO2 Reduction

Abstract: Halide perovskite quantum dots (QDs), primarily regarded as optoelectronic materials for LED and photovoltaic devices, have not been applied for photochemical conversion (e.g., water splitting or CO2 reduction) applications because of their insufficient stability in the presence of moisture or polar solvents. Herein, we report the use of CsPbBr3 QDs as novel photocatalysts to convert CO2 into solar fuels in nonaqueous media. Under AM 1.5G simulated illumination, the CsPbBr3 QDs steadily generated and injected electrons into CO2, catalyzing CO2 reduction at a rate of 23.7 μmol/g h with a selectivity over 99.3%. Additionally, through the construction of a CsPbBr3 QD/graphene oxide (CsPbBr3 QD/GO) composite, the rate of electron consumption increased 25.5% because of improved electron extraction and transport. This study is anticipated to provide new opportunities to utilize halide perovskite QD materials in photocatalytic applications.

Reduced Graphene Oxide-Hierarchical ZnO Hollow Sphere Composites with Enhanced Photocurrent and Photocatalytic Activity

Abstract: The reduced graphene oxide (RGO)-hierarchical ZnO hollow sphere composites are prepared through a simple ultrasonic treatment of the solution containing graphene oxide (GO), Zn(CH3COO)2, DMSO, and H2O. The GO is reduced to RGO effectively, and the ZnO hollow spheres consisting of nanoparticles are uniformly dispersed on the surface of RGO sheets during the ultrasonic process. The optimum synergetic effect of RGO-ZnO composites is found at a RGO mass ratio of 3.56%, and the photocurrent and photodegradation efficiency on methylene blue of RGO-ZnO composites are improved by five times and 67%, respectively, compared with those of pure ZnO hollow spheres. The enhancements of photocurrent and photocatalytic activity can be attributed to the suppression of charge carriers recombination resulting from the interaction between ZnO and RGO.

Novel porous molybdenum tungsten phosphide hybrid nanosheets on carbon cloth for efficient hydrogen evolution

Abstract: Nanostructural modification and chemical composition tuning are paramount to developing effective non-noble hydrogen evolution reaction (HER) catalysts for water splitting. Herein, we report a novel excellent porous molybdenum tungsten phosphide (Mo–W–P) hybrid nanosheet catalyst for hydrogen evolution, which is synthesized via in situ phosphidation of molybdenum tungsten oxide (Mo–W–O) hybrid nanowires grown on carbon cloth. The three-dimensional (3D) hierarchical hybrid electrocatalyst exhibits impressively high electrocatalytic activity with a low overpotential of 138 mV required to achieve a high current density of 100 mA cm−2 and a small Tafel slope of 52 mV dec−1 in 0.5 M H2SO4, which are significantly higher than those of single MoP nanosheets and WP2 nanorods. Such an outstanding performance of the Mo–W–P hybrid electrocatalyst is attributed to the 3D conductive scaffolds, porous nanosheet structure, and strong synergistic effect of W and Mo atoms in Mo–W–P, making it a very promising catalyst for hydrogen production. Our findings demonstrate that careful control over the morphology and composition of the electrocatalyst can achieve highly efficient hybrid electrocatalysts.

Oriented hierarchical single crystalline anatase TiO2 nanowire arrays on Ti-foil substrate for efficient flexible dye-sensitized solar cells

Abstract: Hierarchical anatase TiO2 nanowire (HNW) arrays consisting of long single crystalline nanowire trunks and short single crystalline nanorod branches have been synthesized on Ti-foil substrate via a two-step hydrothermal growth process. The formation of the HNW arrays based on anatase TiO2 nanowire (NW) arrays can be ascribed to the crystallographic relationship between trunk and branch. The power conversion efficiency of dye-sensitized solar cells (DSSCs) based on such a HNW photoelectrode (4.51%) shows a significant enhancement compared to TiO2 nanowire (NW) array photoelectrode (3.12%) with similar thickness (∼15 μm in nanowire length), which can be attributed to more dye loading, superior light scattering ability and comparable electron transport rate for the former. Furthermore, flexible DSSC using TiO2 HNW arrays on Ti substrate as working electrode and transparent PEDOT/ITO-PET prepared via in situelectrodeposition as counter electrode shows a comparable photovoltaic performance to the rigid Pt/FTO-glass cell. A power conversion efficiency as high as 4.32% (Jsc = 7.91 mA cm−2, Voc = 796 mV, FF = 0.69) is obtained for the first time for fully flexible DSSC based on hierarchical TiO2 nanowire arrays and Pt-free counter electrode.

Core@Shell CsPbBr3@Zeolitic Imidazolate Framework Nanocomposite for Efficient Photocatalytic CO2 Reduction

Abstract: The proper energy band structure and excellent visible-light responses enable halide perovskites as potential photocatalysts for CO2 reduction, but the conversion efficiency is still low due to the serious radiative recombination, low CO2 capturing ability, and poor stability. Here we illustrate the design and synthesis of a halide perovskite@metal–organic framework (MOF) composite photocatalyst with enhanced CO2 reduction activity. A facile in situ synthetic procedure is employed to directly grow a zinc/cobalt-based zeolitic imidazolate framework (ZIF) coating on the surface of CsPbBr3 quantum dots. The CsPbBr3@ZIF composite shows largely improved moisture stability, CO2 capturing ability, and charge separation efficiency. Moreover, the catalytic active Co centers in ZIF-67 can further accelerate the charge separation process and activate the adsorbed CO2 molecules, which leads to enhanced catalytic activity for gaseous CO2 reduction. This work would provide new insight for designing excellent perovskite...

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Abstract: Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Titanium dioxide-based nanomaterials for photocatalytic fuel generations.

Abstract: Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States

Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles.

Abstract: Hydrogen fuel is considered as the cleanest renewable resource and the primary alternative to fossil fuels for future energy supply. Sustainable hydrogen generation is the major prerequisite to realize future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the vital step of water electrolysis to H2 production, has been the subject of extensive study over the past decades. In this comprehensive review, we first summarize the fundamentals of HER and review the recent state-of-the-art advances in the low-cost and high-performance catalysts based on noble and non-noble metals, as well as metal-free HER electrocatalysts. We systemically discuss the insights into the relationship among the catalytic activity, morphology, structure, composition, and synthetic method. Strategies for developing an effective catalyst, including increasing the intrinsic activity of active sites and/or increasing the number of active sites, are summarized and highlighted. Finally, the challenges, perspectives, and research directions of HER electrocatalysis are featured.

Cocatalysts for Selective Photoreduction of CO2 into Solar Fuels.

Abstract: Photoreduction of CO2 into sustainable and green solar fuels is generally believed to be an appealing solution to simultaneously overcome both environmental problems and energy crisis. The low selectivity of challenging multi-electron CO2 photoreduction reactions makes it one of the holy grails in heterogeneous photocatalysis. This Review highlights the important roles of cocatalysts in selective photocatalytic CO2 reduction into solar fuels using semiconductor catalysts. A special emphasis in this review is placed on the key role, design considerations and modification strategies of cocatalysts for CO2 photoreduction. Various cocatalysts, such as the biomimetic, metal-based, metal-free, and multifunctional ones, and their selectivity for CO2 photoreduction are summarized and discussed, along with the recent advances in this area. This Review provides useful information for the design of highly selective cocatalysts for photo(electro)reduction and electroreduction of CO2 and complements the existing reviews on various semiconductor photocatalysts.

Non-Noble Metal-based Carbon Composites in Hydrogen Evolution Reaction: Fundamentals to Applications.

Abstract: Hydrogen has been hailed as a clean and sustainable alternative to finite fossil fuels in many energy systems. Water splitting is an important method for hydrogen production in high purity and large quantities. To accelerate the hydrogen evolution reaction (HER) rate, it is highly necessary to develop high efficiency catalysts and to select a proper electrolyte. Herein, the performances of non-noble metal-based carbon composites under various pH values (acid, alkaline and neutral media) for HER in terms of catalyst synthesis, structure and molecular design are systematically discussed. A detailed analysis of the structure-activity-pH correlations in the HER process gives an insight on the origin of the pH-dependence for HER, and provide guidance for future HER mechanism studies on non-noble metal-based carbon composites. Furthermore, this Review gives a fresh impetus to rational design of high-performance noble-metal-free composites catalysts and guide researchers to employ the established electrocatalysts in proper water electrolysis technologies.