UiO‐66, a zirconium based metal–organic framework, is incorporated with nanosized carbon nitride nanosheets via a facile electrostatic self‐assembly method. This hybrid structure exhibits a large ...surface area and strong CO2 capture ability due to the introduction of UiO‐66. We demonstrate that electrons from the photoexcited carbon nitride nanosheet can transfer to UiO‐66, which can substantially suppress electron–hole pair recombination in the carbon nitride nanosheet, as well as supply long‐lived electrons for the reduction of CO2 molecules that are adsorbed in UiO‐66. As a result, the UiO‐66/carbon nitride nanosheet heterogeneous photocatalyst exhibits a much higher photocatalytic activity for the CO2 conversion than that of bare carbon nitride nanosheets. We believe this self‐assembly method can be extended to other carbon nitride nanosheet loaded materials.
A novel carbon nitride nanosheet heterogeneous photocatalyst is fabricated via a facile electrostatic self‐assembly method. Electrons from the photoexcited carbon nitride nanosheets can transfer to UiO‐66, which can substantially suppress electron–hole pair recombination in the carbon nitride nanosheet, as well as supply long‐lived electrons for the reduction of CO2 molecules adsorbed in UiO‐66.
Surface modulation at the atomic level is an important approach for tuning surface chemistry and boosting the catalytic performance. Here, a surface modulation strategy is demonstrated through the ...decoration of isolated Ni atoms onto the basal plane of hierarchical MoS2 nanosheets supported on multichannel carbon nanofibers for boosted hydrogen evolution activity. X‐ray absorption fine structure investigation and density functional theory (DFT) calculation reveal that the MoS2 surface decorated with isolated Ni atoms displays highly strengthened H binding. Benefiting from the unique tubular structure and basal plane modulation, the newly developed MoS2 catalyst exhibits excellent hydrogen evolution activity and stability. This single‐atom modification strategy opens up new avenues for tuning the intrinsic catalytic activity toward electrocatalytic water splitting and other energy‐related processes.
Surface modulation at the atomic level has been an important approach for boosting the performance of electrocatalysts. Here, a combined theoretical and experimental study on Ni atom decorated hierarchical MoS2 nanosheets supported on a multichannel carbon matrix (MCM) is presented. The obtained hybrid MCM@MoS2–Ni electrocatalyst with activated S sites exhibits high performance in electrocatalytic hydrogen evolution.
Highlights
All the coordination engineering strategies, such as tuning the coordination species, the coordination number of the active centers, heteroatoms interactions within the support, synergetic ...interaction between neighboring metal monomers, and spatial microenvironment, have been summarized and discussed in detail.
Various single-atom catalysts (SACs) with different coordination spheres in energy conversion driven by thermal, light and electric energy have been systematically reviewed.
The current key challenges in SACs for energy conversion are pointed out, and some potential strategies/perspectives are proposed.
Reducing the dimensions of metallic nanoparticles to isolated, single atom has attracted considerable attention in heterogeneous catalysis, because it significantly improves atomic utilization and often leads to distinct catalytic performance. Through extensive research, it has been recognized that the local coordination environment of single atoms has an important influence on their electronic structures and catalytic behaviors. In this review, we summarize a series of representative systems of single-atom catalysts, discussing their preparation, characterization, and structure–property relationship, with an emphasis on the correlation between the coordination spheres of isolated reactive centers and their intrinsic catalytic activities. We also share our perspectives on the current challenges and future research promises in the development of single-atom catalysis. With this article, we aim to highlight the possibility of finely tuning the catalytic performances by engineering the coordination spheres of single-atom sites and provide new insights into the further development for this emerging research field.
Exploring highly efficient electrocatalysts for the oxygen evolution reaction (OER) and unveiling their activity origin are pivotal for energy conversion technologies. Herein, atomically distributed ...Ni sites over a N‐doped hollow carbon matrix are reported as a promising electrocatalyst for OER in alkaline conditions. Significantly boosted activity is observed after the decoration of the active Ni sites with well‐controlled coordination geometry. Results of X‐ray absorption spectroscopy investigation and density functional theory (DFT) calculation reveal that the effective electronic coupling via the Ni–N coordination can move down the Fermi level and lower the adsorption energy of intermediates, thus resulting in the facilitated OER kinetics.
A well‐defined Ni single‐atom catalyst supported on a N‐doped carbon matrix is synthesized and used as a model system for corroborating the measured electrocatalytic activity for the oxygen evolution reaction (OER) with theoretically computed adsorption energetics. This work unveils the dominant electroactive centers of the Ni–N sites for the OER, which can shed light on future design of efficient electrocatalysts.
Exploring novel functional materials is of vital importance in the development of science and technology, and thus beneficial to our daily life. Metal-organic frameworks (MOFs) and their composites ...as well as derivatives, with high porosity and tailorable chemical components, have drawn increasing interest in gas storage, energy conversion, and environment remediation in the past decades. This review highlights recent achievements on applications of MOF-based materials in the renewable energy and environmental science. Specifically, the developments and advantages of MOF-based materials are first presented and discussed. We then focus on the fabrication strategies of MOF-based materials and their applications in areas including gas adsorption, energy conversion, and storage. The well-established findings provide an in-depth understanding for the construction and application of these advanced materials. This review concludes with some outlooks for the fields of energy conversion and environmental science by using MOF-based materials.
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Metal-organic frameworks (MOFs), also known as porous coordination polymers, have attracted great interest as one of the best examples of materials constructed from molecular engineering with high porosity, organic-inorganic hybrid nature, synthetic advantages, and inherent presence of coordinated metal and heteroatoms. Constructing MOF-based materials, including pristine MOFs and their composites as well as their derivatives for renewable energy and environmental applications, is a newly emerging but fast-growing field owing to their remarkable advantages in structural optimization and component design. In the present review, we provide a comprehensive overview focusing on the utilization of MOF-based materials in niche areas of gas adsorption, energy conversion, and storage.
Specifically, the development and advantages of MOF-based materials are first presented and discussed. We then highlight the recent progress of the fabrication strategies and the applications of MOF-based materials in hydrogen (H2) adsorption and evolution, CO2 storage and conversion, catalysis of oxygen (O2), rechargeable batteries, supercapacitors, and solar cells. The great flexibility in design and synthesis of MOFs enables MOF-based materials with tailorable compositions, morphologies, structures, properties, and functionalities to be a highly versatile and tunable platform for renewable clean energy and environmental remediation. Lastly, the challenges associated with the development of MOF-based materials are summarized and some possible research directions are proposed for further improvement of these novel functional materials in the fields of energy conversion and environmental science.
Construction of metal-organic framework (MOF)-based materials is a newly emerging but fast-growing field, which has shown huge impact on many renewable energy and environmental applications such as gas adsorption, energy conversion, and storage. The great flexibility in design and synthesis of MOFs enables the MOF-based materials to be highly attractive for modern applications. In this review, we present the latest progress on the design and synthesis of MOFs and their composites as well as derivatives for energy and environmental applications.
Through a facile and effective strategy by employing lithium molten salts the controlled synthesis of 2H‐ and 1T‐MoS2 monolayers with high‐yield production is achieved. Both phases of MoS2 monolayers ...exhibit high stabilities. When used as a catalyst for hydrogen evolution, these phased MoS2 monolayers deliver respective advantages in the field of electro‐ and photo‐catalytic hydrogen evolution.
A simple method is developed to fabricate protonated porous graphitic carbon nitride nanosheets (P‐PCNNS) by protonation–exfoliation of bulk graphitic carbon nitride (BCN) with phosphoric acid ...(H3PO4). The H3PO4 treatment not only helps to exfoliate the BCN into 2D ultrathin nanosheets with abundant micro‐ and mesopores, endowing P‐PCNNS with more exposed active catalytic sites and cross‐plane diffusion channels to facilitate the mass and charge transport, but also induces the protonation of carbon nitride polymer, leading to the moderate removal of the impurities of carbon species in BCN for the optimization of the aromatic π‐conjugated system for better charge separation without changing its chemical structure. As a result, the P‐PCNNS show much higher photocatalytic performance for hydrogen evolution and CO2 conversion than bare BCN and graphitic carbon nitride nanosheets.
A facile approach is developed to fabricate protonated porous g‐C3N4 nanosheets by protonation–exfoliation of bulk g‐C3N4 with phosphoric acid. The prepared protonated porous g‐C3N4 nanosheets exhibit a micro/mesoporous structure and an optimized aromatic π‐conjugated system and show a dramatically improved photocatalytic performance for H2 evolution and CO2 conversion than bulk g‐C3N4 and g‐C3N4 nanosheets.
Developing electrocatalytic energy conversion technologies for replacing the traditional energy source is highly expected to resolve the fossil fuel exhaustion and related environmental problems. ...Exploring stable and high‐efficiency electrocatalysts is of vital importance for the promotion of these technologies. Single‐atom catalysts (SACs), with atomically distributed active sites on supports, perform as emerging materials in catalysis and present promising prospects for a wide range of applications. The rationally designed near‐range coordination environment, long‐range electronic interaction and microenvironment of the coordination sphere cast huge influence on the reaction mechanism and related catalytic performance of SACs. In the current Review, some recent developments of atomically dispersed reactive centers for electrocatalytic CO2 reduction and water splitting are well summarized. The catalytic mechanism and the underlying structure–activity relationship are elaborated based on the recent progresses of various operando investigations. Finally, by highlighting the challenges and prospects for the development of single‐atom catalysis, we hope to shed some light on the future research of SACs for the electrocatalytic energy conversion.
This Review summarizes the recent developments of atomically dispersed reactive centers for electrocatalytic CO2 reduction and water splitting. The catalytic mechanisms and the underlying structure–activity relationships are well elaborated based on the recent progress from the operando investigations.
Modular optimization of metal–organic frameworks (MOFs) was realized by incorporation of coordinatively unsaturated single atoms in a MOF matrix. The newly developed MOF can selectively capture and ...photoreduce CO2 with high efficiency under visible‐light irradiation. Mechanistic investigation reveals that the presence of single Co atoms in the MOF can greatly boost the electron–hole separation efficiency in porphyrin units. Directional migration of photogenerated excitons from porphyrin to catalytic Co centers was witnessed, thereby achieving supply of long‐lived electrons for the reduction of CO2 molecules adsorbed on Co centers. As a direct result, porphyrin MOF comprising atomically dispersed catalytic centers exhibits significantly enhanced photocatalytic conversion of CO2, which is equivalent to a 3.13‐fold improvement in CO evolution rate (200.6 μmol g−1 h−1) and a 5.93‐fold enhancement in CH4 generation rate (36.67 μmol g−1 h−1) compared to the parent MOF.
Less is more: A photocatalyst comprising atomically dispersed Co in an extended MOF efficiently reduces CO2. Directional migration of photogenerated excitons from porphyrin to catalytic cobalt centers was witnessed, thereby supplying long‐lived electrons for reduction of CO2 molecules adsorbed on cobalt centers.
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