Solar-to-chemical energy conversion via heterogeneous photocatalysis is one of the sustainable approaches to tackle the growing environmental and energy challenges. Among various promising ...photocatalytic materials, plasmonic-driven photocatalysts feature prominent solar-driven surface plasmon resonance (SPR). Non-noble plasmonic metals (NNPMs)-based photocatalysts have been identified as a unique alternative to noble metal-based ones due to their advantages like earth-abundance, cost-effectiveness, and large-scale application capability. This review comprehensively summarizes the most recent advances in the synthesis, characterization, and properties of NNPMs-based photocatalysts. After introducing the fundamental principles of SPR, the attributes and functionalities of NNPMs in governing surface/interfacial photocatalytic processes are presented. Next, the utilization of NNPMs-based photocatalytic materials for the removal of pollutants, water splitting, CO2 reduction, and organic transformations is discussed. The review concludes with current challenges and perspectives in advancing the NNPMs-based photocatalysts, which are timely and important to plasmon-based photocatalysis, a truly interdisciplinary field across materials science, chemistry, and physics.
Semiconductor‐based photocatalysis is considered to be an attractive way for solving the worldwide energy shortage and environmental pollution issues. Since the pioneering work in 2009 on graphitic ...carbon nitride (g‐C3N4) for visible‐light photocatalytic water splitting, g‐C3N4‐based photocatalysis has become a very hot research topic. This review summarizes the recent progress regarding the design and preparation of g‐C3N4‐based photocatalysts, including the fabrication and nanostructure design of pristine g‐C3N4, bandgap engineering through atomic‐level doping and molecular‐level modification, and the preparation of g‐C3N4‐based semiconductor composites. Also, the photocatalytic applications of g‐C3N4‐based photocatalysts in the fields of water splitting, CO2 reduction, pollutant degradation, organic syntheses, and bacterial disinfection are reviewed, with emphasis on photocatalysis promoted by carbon materials, non‐noble‐metal cocatalysts, and Z‐scheme heterojunctions. Finally, the concluding remarks are presented and some perspectives regarding the future development of g‐C3N4‐based photocatalysts are highlighted.
Polymeric g‐C3N4‐based photocatalysts are very attractive due to their unique electronic and physicochemical properties, which make them well suited for various applications, such as photocatalytic water splitting, CO2 reduction, pollutant degradation, organic syntheses, and bacterial disinfection. These unique properties can be achieved by optimized preparation, nanostructural design, and bandgap engineering of g‐C3N4, as well as by the construction of g‐C3N4‐based semiconductor heterojunctions.
Ever‐increasing fossil‐fuel combustion along with massive CO2 emissions has aroused a global energy crisis and climate change. Photocatalytic CO2 reduction represents a promising strategy for clean, ...cost‐effective, and environmentally friendly conversion of CO2 into hydrocarbon fuels by utilizing solar energy. This strategy combines the reductive half‐reaction of CO2 conversion with an oxidative half reaction, e.g., H2O oxidation, to create a carbon‐neutral cycle, presenting a viable solution to global energy and environmental problems. There are three pivotal processes in photocatalytic CO2 conversion: (i) solar‐light absorption, (ii) charge separation/migration, and (iii) catalytic CO2 reduction and H2O oxidation. While significant progress is made in optimizing the first two processes, much less research is conducted toward enhancing the efficiency of the third step, which requires the presence of cocatalysts. In general, cocatalysts play four important roles: (i) boosting charge separation/transfer, (ii) improving the activity and selectivity of CO2 reduction, (iii) enhancing the stability of photocatalysts, and (iv) suppressing side or back reactions. Herein, for the first time, all the developed CO2‐reduction cocatalysts for semiconductor‐based photocatalytic CO2 conversion are summarized, and their functions and mechanisms are discussed. Finally, perspectives in this emerging area are provided.
Active and stable CO2‐reduction cocatalysts can obviously enhance the efficiency, selectivity, and stability of semiconductor‐based photocatalytic CO2 reduction. All of the developed CO2‐reduction cocatalysts are summarized, and their functions and insightful mechanisms are discussed. This can pave new avenues to the exploration of novel highly active and selective cocatalysts, toward high‐performance solar fuel production.
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Colloidal silica particles have received a widespread interest because of their potential applications in adsorption, ceramics, catalysis, drug delivery and more. Among many ...approaches towards fabrication of these colloidal particles, Stöber, Fink and Bohn (SFB) method, known as Stöber synthesis is an effective sol–gel strategy for production of uniform, monodispersed silica particles with highly tailorable size and surface properties. This review, after a brief introduction showing the importance of colloidal chemistry, is focused on the Stöber synthesis of silica spheres including discussion of the key factors affecting their particle size, porosity and surface properties. Next, further developments of this method are presented toward fabrication of polymer, carbon, and composite spheres.
Hybrid porous nanowire arrays composed of strongly interacting Co3O4 and carbon were prepared by a facile carbonization of the metal–organic framework grown on Cu foil. The resulting material, ...possessing a high surface area of 251 m2 g–1 and a large carbon content of 52.1 wt %, can be directly used as the working electrode for oxygen evolution reaction without employing extra substrates or binders. This novel oxygen evolution electrode can smoothly operate in alkaline solutions (e.g., 0.1 and 1.0 M KOH), affording a low onset potential of 1.47 V (vs reversible hydrogen electrode) and a stable current density of 10.0 mA cm–2 at 1.52 V in 0.1 M KOH solution for at least 30 h, associated with a high Faradaic efficiency of 99.3%. The achieved ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the state-of-the-art noble-metal/transition-metal and nonmetal catalysts, originate from the unique nanowire array electrode configuration and in situ carbon incorporation, which lead to the large active surface area, enhanced mass/charge transport capability, easy release of oxygen gas bubbles, and strong structural stability. Furthermore, the hybrid Co3O4-carbon porous nanowire arrays can also efficiently catalyze oxygen reduction reaction, featuring a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal–air batteries, regenerative fuel cells, and other important clean energy devices.
Compared to modern fossil‐fuel‐based refineries, the emerging electrocatalytic refinery (e‐refinery) is a more sustainable and environmentally benign strategy to convert renewable feedstocks and ...energy sources into transportable fuels and value‐added chemicals. A crucial step in conducting e‐refinery processes is the development of appropriate reactions and optimal electrocatalysts for efficient cleavage and formation of chemical bonds. However, compared to well‐studied primary reactions (e.g., O2 reduction, water splitting), the mechanistic aspects and materials design for emerging complex reactions are yet to be settled. To address this challenge, herein, we first present fundamentals of heterogeneous electrocatalysis and some primary reactions, and then implement these to establish the framework of e‐refinery by coupling in situ generated intermediates (integrated reactions) or products (tandem reactions). We also present a set of materials design principles and strategies to efficiently manipulate the reaction intermediates and pathways.
The concept of the electrocatalytic refinery (e‐refinery) is an intrinsically sustainable strategy to convert renewable feedstocks and energy sources to transportable fuels and value‐added chemicals. This Review describes the concept, fundamentals, and framework of e‐refinery processes with some game‐changing reactions and innovative catalyst design strategies.
Control of TiO2 crystal facets has attracted enormous interest due to the fascinating shape-dependent photocatalytic activity of this material. In this work, the effect of the ratio of {001} and ...{101} facets on the photocatalytic CO2-reduction performance of anatase TiO2 is reported. A new “surface heterojunction” concept is proposed on the basis of the density functional theory (DFT) calculations to explain the difference in the photocatalytic activity of TiO2 with coexposed {001} and {101} facets.
The lack of chemical understanding and efficient catalysts impedes the development of electrocatalytic nitrogen reduction reaction (eNRR) for ammonia production. In this work, we employed density ...functional theory calculations to build up a picture (activity trends, electronic origins, and design strategies) of single-atom catalysts (SACs) supported on nitrogen-doped carbons as eNRR electrocatalysts. To construct such a picture, this work presents systematic studies of the eNRR activity of SACs covering 20 different transition metal (TM) centers coordinated by nitrogen atoms contained in three types of nitrogen-doped carbon substrates, which gives 60 SACs. Our study shows that the intrinsic activity trends could be established on the basis of the nitrogen adatom adsorption energy (ΔE N*). Furthermore, the influence of metal and support (ligands) on ΔE N* proved to be related to the bonding/antibonding orbital population and regulating the scaling relations for adsorption of intermediates, respectively. Accordingly, a two-step strategy is proposed for improving the eNNR activity of TM-SACs, which involves the following: (i) selection of the most promising family of SACs (g-C3N4 supported SACs as predicted in this work) and (ii) further improvement of the activity of the best candidate in the aforementioned family via tuning the adsorption strength of the key intermediates. Also, the stability of N-doped carbon supports and their selectivity in comparison to the competing hydrogen evolution need to be taken into consideration for screening the durable and efficient candidates. Finally, an effective strategy for designing active, stable, and selective SACs based on the mechanistic insights is elaborated to guide future eNRR studies.
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Metal–organic frameworks (MOFs) have attracted a special attention due to outstanding porosity, adjustable pore sizes, and huge opportunities in varying organic–inorganic ...compositions. Enormous studies conducted so far on MOFs indicate their high potential in catalysis, gas adsorption, drug delivery, water treatment, energy storage, among others. However, mass production of MOFs is still limited mainly due to the non-economic, non-green and complex synthesis methods. Mechanochemistry is an alternative solution for efficient and environmentally friendly syntheses of various MOFs. Fast and solvent-free or solvent-less mechanosynthesis seems to be a very powerful versatile method for obtaining these advanced porous materials. The mechanochemical concept was used for the preparation of various MOFs including the most popular structures: MOF-5, ZIF-8, HKUST-1, MIL-101, UiO-66. These MOFs feature high specific surface areas, comparable to those prepared by conventional solvent-based methods. Furthermore, mechanochemistry was successfully used for the synthesis of non-conventional multimetallic MOFs and previously unreported solid phases. This review shows the recent developments, challenges and perspectives of green synthesis of diverse MOF structures using mechanochemistry. Besides describing the mechanochemical synthesis of MOFs, some achievements in green applications are also summarized. Importantly, current trends in research suggests for further development of these fields i.e., harmful gas adsorption, water treatment, and energy storage.
The mutually corroborated electrochemical measurements and density functional theory (DFT) calculations were used to uncover the origin of electrocatalytic activity of graphene-based electrocatalysts ...for oxygen reduction reaction (ORR). A series of graphenes doped with nonmetal elements was designed and synthesized, and their ORR performance was evaluated in terms of four electrochemical descriptors: exchange current density, on-set potential, reaction pathway selectivity and kinetic current density. It is shown that these descriptors are in good agreement with DFT calculations, allowing derivation of a volcano plot between the ORR activity and the adsorption free energy of intermediates on metal-free materials, similarly as in the case of metallic catalysts. The molecular orbital concept was used to justify this volcano plot, and to theoretically predict the ORR performance of an ideal graphene-based catalyst, the ORR activity of which is comparable to the state-of-the-art Pt catalyst. Moreover, this study may stimulate the development of metal-free electrocatalysts for other key energy conversion processes including hydrogen evolution and oxygen evolution reactions and largely expand the spectrum of catalysts for energy-related electrocatalysis reactions.
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