Author
Fan Xu
Bio: Fan Xu is an academic researcher from Zhejiang University. The author has contributed to research in topics: Catalysis & Benzoic acid. The author has an hindex of 10, co-authored 10 publications receiving 2086 citations.
Papers
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TL;DR: 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 provides guidance for future HER mechanism studies on non-noble metal-based carbon composites.
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.
1,258 citations
TL;DR: Inspired by the leavening of bread, the authors designed a strategy to fabricate hierarchical porous carbons with 3D hierarchical pores consisting of macro, meso, and micropores.
377 citations
TL;DR: In this article, the earth-abundant nanohybrids Co0/Co3O4@N-doped carbon nanotubes were fabricated via an efficient thermal condensation of d-glucosamine hydrochloride, melamine, and Co(NO3)2·6H2O.
Abstract: The earth-abundant nanohybrids Co0/Co3O4@N-doped carbon nanotubes were fabricated via an efficient thermal condensation of d-glucosamine hydrochloride, melamine, and Co(NO3)2·6H2O. The hybrids furnish excellent catalytic activity and perfect chemoselectivity (>99%) for a wide range of substituted nitroarenes (21 examples) under relatively mild conditions. The high catalytic performance and durability is attributed to the synergistic effects between each component, the unique structure of graphene layers-coated Co0, and the electronic activation of doped nitrogen. Density functional calculations indicate that the inner Co0 core and N species on the carbon shell can significantly decrease the dissociation energies of H2, giving evidence of the ability of carbon shell in the hybrids to enable H2 activation. These results open up an avenue to design more powerful low-cost catalysts for industrial applications.
341 citations
TL;DR: In this article, the fabrication methods for nitrogen-doped porous carbon (NPC) materials used in heterogeneous hydrogenation and oxidations and highlight the intrinsic catalytic mechanisms along with the catalyst design strategies.
227 citations
TL;DR: In this article, a superior OER catalyst of Fe substituted α-Co(OH)2 (α-Co1−mFem(OH)-2) has been synthesized by taking advantage of the large layered structure and good conductivity of αCo(O)2, in conjunction with the rich redox properties and abundance of Fe.
Abstract: Cost-effective and highly active electrocatalysts for the oxygen evolution reaction (OER) are critical to energy conversion and storage processes. Herein, a superior OER catalyst of Fe substituted α-Co(OH)2 (α-Co1−mFem(OH)2) has been synthesized by taking advantage of the large layered structure and good conductivity of α-Co(OH)2, in conjunction with the rich redox properties and abundance of Fe. The atomically layered α-Co4Fe(OH)x (Co/Fe = 4) nanoplates could effectively catalyze water oxidation at the onset potential of 0.26 V and its turnover frequency (TOF) was 11 and 5 times higher than those of α-Co(OH)2 and IrO2, respectively. The increased activity could be attributed to strong electronic interactions between Co and Fe. Density functional theory (DFT) calculations also demonstrated that the theoretical overpotential of α-Co1−mFem(OH)2 is obviously lower than that of α-Co(OH)2 and thus Fe doped α-Co(OH)2 displays a better activity. Moreover, the correlation between the Fe content and activity could be plotted as a volcano curve.
200 citations
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TL;DR: A novel hybrid nanostructure with CoP nanoparticles embedded in a N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis-oxidation-phosphidation strategy derived from core-shell ZIF-8@ZIF-67 is reported, benefiting from the synergistic effects between highly active CoP NPs and NCNHP.
Abstract: The construction of highly active and stable non-noble-metal electrocatalysts for hydrogen and oxygen evolution reactions is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP nanoparticles (NPs) embedded in a N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis–oxidation–phosphidation strategy derived from core–shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances. When the CoP/NCNHP was employed as both the anode and cathode for overall water splitting, a potential as low as 1.64 V was needed to achieve the current density of 10 mA·cm–2, and it still exhibited superior activity after continuously working for 36 h with nearly negligible decay in potential. Density functional theory calculations indicated that the electron transfer from NCNHP to CoP could increase the electronic states of the Co d-orbital a...
1,411 citations
TL;DR: The fundamentals of HER are summarized and 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 are reviewed.
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.
1,387 citations
TL;DR: 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.
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.
1,365 citations
TL;DR: 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 provides guidance for future HER mechanism studies on non-noble metal-based carbon composites.
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.
1,258 citations
TL;DR: The state-of-the-art advancements in FSSCs are reviewed to provide new insights on mechanisms, emerging electrode materials, flexible gel electrolytes and novel cell designs.
Abstract: Flexible solid-state supercapacitors (FSSCs) are frontrunners in energy storage device technology and have attracted extensive attention owing to recent significant breakthroughs in modern wearable electronics In this study, we review the state-of-the-art advancements in FSSCs to provide new insights on mechanisms, emerging electrode materials, flexible gel electrolytes and novel cell designs The review begins with a brief introduction on the fundamental understanding of charge storage mechanisms based on the structural properties of electrode materials The next sections briefly summarise the latest progress in flexible electrodes (ie, freestanding and substrate-supported, including textile, paper, metal foil/wire and polymer-based substrates) and flexible gel electrolytes (ie, aqueous, organic, ionic liquids and redox-active gels) Subsequently, a comprehensive summary of FSSC cell designs introduces some emerging electrode materials, including MXenes, metal nitrides, metal–organic frameworks (MOFs), polyoxometalates (POMs) and black phosphorus Some potential practical applications, such as the development of piezoelectric, photo-, shape-memory, self-healing, electrochromic and integrated sensor-supercapacitors are also discussed The final section highlights current challenges and future perspectives on research in this thriving field
1,210 citations