The reaction of precursors containing both nitrogen and oxygen atoms with NiII under 500 °C can generate a N/O mixing coordinated Ni‐N3O single‐atom catalyst (SAC) in which the oxygen atom can be ...gradually removed under high temperature due to the weaker Ni−O interaction, resulting in a vacancy‐defect Ni‐N3‐V SAC at Ni site under 800 °C. For the reaction of NiII with the precursor simply containing nitrogen atoms, only a no‐vacancy‐defect Ni‐N4 SAC was obtained. Experimental and DFT calculations reveal that the presence of a vacancy‐defect in Ni‐N3‐V SAC can dramatically boost the electrocatalytic activity for CO2 reduction, with extremely high CO2 reduction current density of 65 mA cm−2 and high Faradaic efficiency over 90 % at −0.9 V vs. RHE, as well as a record high turnover frequency of 1.35×105 h−1, much higher than those of Ni‐N4 SAC, and being one of the best reported electrocatalysts for CO2‐to‐CO conversion to date.
A vacancy defect was controllably constructed at the Ni site in a nickel single‐atom catalyst. It shows significantly enhanced electrocatalytic activity and selectivity for CO2‐to‐CO conversion compared with the Ni‐N4 catalyst.
Regulating intermediates through elaborate catalyst design to control the reaction direction is crucial for promoting the selectivity of electrocatalytic CO2‐to‐CH4. M−C (M=metal) bonds are ...particularly important for tuning the multi‐electron reaction; however, its construction in nanomaterials is challenging. Here, via rational design of in situ anchoring of Cu SAs (single atoms) on the unique platform graphdiyne, we firstly realize the construction of a chemical bond Cu−C (GDY). In situ Raman spectroelectrochemistry and DFT calculations confirm that due to the fabrication of the Cu−C bond, during CO2 reduction, the formation of *OCHO intermediates is dominant rather than *COOH on Cu atoms, facilitating the formation of CH4. Therefore, we find that constructing the Cu−C bond in Cu SAs/GDY can supply an efficient charge transfer channel, but most importantly control the reaction intermediates and guide a more facile reaction pathway to CH4, thereby significantly boosting its catalytic performance. This work provides new insights on enhancing the selectivity for CO2RR at the atomic level.
The interfacial chemical Cu−C bond is successfully constructed through in situ anchoring Cu SAs (single atoms) on the unique platform graphdiyne. Experimental results and theoretical calculations demonstrate that due to the existence of the Cu−C bond, the formation of *OCHO intermediates dominates and promotes the production of CH4.
As a special carbon material, graphdiyne (GDY) features the superiorities of incomplete charge transfer effect on the atomic level, tunable electronic structure and anchoring metal atoms directly ...with organometallic coordination bonds M (metal)‐C (alkynyl carbon in GDY), providing it an ideal platform to construct single‐atom catalysts (ACs). The coordination environment of single atoms anchored on GDY plays a key role in their catalytic performance. The mini‐review highlights state‐of‐the‐art progress in the rational design of GDY‐based ACs and their applications, and mainly reveals the relationship between the coordination engineering of the GDY‐based ACs and corresponding catalytic performance. Finally, some prospects concerning the future development of GDY‐based ACs in energy conversion are also discussed.
This review presents the properties of graphdiyne (GDY), the recent progress in the development of GDY‐based atomic catalysts (ACs), especially their applications in energy conversion, and reveals the relationship between the coordination engineering of GDY‐based ACs and their catalytic performance. Future challenges and opportunities are also discussed.
The catalytic activity of metal clusters is closely related with the support; however, knowledge on the influence of the support on the catalytic activity is scarce. We demonstrate that Pt ...nanoclusters (NCs) anchored on porous TiO2 nanosheets with rich oxygen vacancies (VO‐rich Pt/TiO2) and deficient oxygen vacancies (VO‐deficient Pt/TiO2), display significantly different catalytic activity for the hydrogen evolution reaction (HER), in which VO‐rich Pt/TiO2 shows a mass activity of 45.28 A mgPt−1 at −0.1 V vs. RHE, which is 16.7 and 58.8 times higher than those of VO‐deficient Pt/TiO2 and commercial Pt/C, respectively. DFT calculations and in situ Raman spectra suggest that porous TiO2 with rich oxygen vacancies can simultaneously achieve reversed charge transfer (electrons transfer from TiO2 to Pt NCs) and enhanced hydrogen spillover from Pt NCs to the TiO2 support, which leads to electron‐rich Pt NCs being amenable to proton reduction of absorbed H*, as well as the acceleration of hydrogen desorption at Pt catalytic sites—both promoting the HER. Our work provides a new strategy for rational design of highly efficient HER catalysts.
The formation of oxygen vacancies in VO‐rich Pt/TiO2 optimizes the Gibbs free energy for hydrogen intermediate adsorption on Pt clusters, and promotes the hydrogen spillover effect from Pt clusters to the TiO2 support, which boosts the electrocatalytic hydrogen evolution reaction.
Two Pt single‐atom catalysts (SACs) of Pt‐GDY1 and Pt‐GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDY through the coordination interactions between Pt atoms ...and alkynyl C atoms in GDY, with the formation of five‐coordinated C1‐Pt‐Cl4 species in Pt‐GDY1 and four‐coordinated C2‐Pt‐Cl2 species in Pt‐GDY2. Pt‐GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with a mass activity up to 3.3 and 26.9 times more active than Pt‐GDY1 and the state‐of‐the‐art commercial Pt/C catalysts, respectively. Pt‐GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbs free energy of the hydrogen adsorption (|ΔGPtH*
|) at the Pt active sites, which are responsible for its excellent catalytic performance. This work can help better understand the structure–catalytic activity relationship in Pt SACs.
All by their selves: Two Pt single‐atom catalysts, anchored on the support of graphdiyne with tuned coordination environments, were developed. Their structure–catalytic performance relationship for hydrogen evolution were investigated.
Improving the stability of lead halide perovskite quantum dots (QDs) in a system containing water is the key for their practical application in artificial photosynthesis. Herein, we encapsulate ...low‐cost CH3NH3PbI3 (MAPbI3) perovskite QDs in the pores of earth‐abundant Fe‐porphyrin based metal organic framework (MOF) PCN‐221(Fex) by a sequential deposition route, to construct a series of composite photocatalysts of MAPbI3@PCN‐221(Fex) (x=0–1). Protected by the MOF the composite photocatalysts exhibit much improved stability in reaction systems containing water. The close contact of QDs to the Fe catalytic site in the MOF, allows the photogenerated electrons in the QDs to transfer rapidly the Fe catalytic sites to enhance the photocatalytic activity for CO2 reduction. Using water as an electron source, MAPbI3@PCN‐221(Fe0.2) exhibits a record‐high total yield of 1559 μmol g−1 for photocatalytic CO2 reduction to CO (34 %) and CH4 (66 %), 38 times higher than that of PCN‐221(Fe0.2) in the absence of perovskite QDs.
Pores and dots: CH3NH3PbI3 (MAPbI3) perovskite quantum dots were encapsulated in the pores of iron‐porphyrin derived metal–organic frameworks (MOFs) of PCN‐221(Fex) to give an efficient photocatalytic system, which has significantly enhanced catalytic efficiency and stability for visible‐light‐driven CO2 reduction using water as an electron source.
The design and synthesis of efficient metal‐free photoelectrocatalysts for water splitting are of great significance, as nonmetal elements are generally earth abundant and environment friendly. As a ...typical metal‐free semiconductor, g‐C3N4 has received much attention in the field of photocatalytic water splitting. However, the poor photoinduced hole mobility of g‐C3N4 restrains its catalytic performance. Herein, for the first time, graphdiyne (GDY) is used to interact with g‐C3N4 to construct a metal‐free 2D/2D heterojunction of g‐C3N4/GDY as an efficient photoelectrocatalyst for water splitting. The g‐C3N4/GDY photocathode exhibits enhanced photocarriers separation due to excellent hole transfer nature of graphdiyne and the structure of 2D/2D heterojunction of g‐C3N4/GDY, realizing a sevenfold increase in electron life time (610 μs) compared to that of g‐C3N4 (88 μs), and a threefold increase in photocurrent density (−98 μA cm−2) compared to that of g‐C3N4 photocathode (−32 μA cm−2) at a potential of 0 V versus normal hydrogen electrode (NHE) in neutral aqueous solution. The photoelectrocatalytic performance can be further improved by fabricating Pt@g‐C3N4/GDY, which displays an photocurrent of −133 μA cm−2 at a potential of 0 V versus NHE in neutral aqueous solution. This work provides a new strategy for the design of efficient metal‐free photoelectrocatalysts for water splitting.
A metal‐free 2D/2D heterojunction of graphitic carbon nitride/graphdiyne on a 3D graphdiyne nanosheet array (g‐C3N4/GDY) is constructed for improving the hole transfer kinetics of g‐C3N4, in which g‐C3N4/GDY shows much higher photoelectron catalytic performance for water splitting than g‐C3N4 due to the high hole transfer rate in graphdiyne and ultrathin 2D/2D heterojunction of g‐C3N4/GDY.
It is common that different crystal facets in metal and metal oxide nanocrystals display different catalytic performances, whereas such phenomena have been rarely documented in metal–organic ...frameworks (MOFs). Herein, we demonstrate for the first time that a nickel metal–organic layer (MOL) exposing rich (100) crystal facets (Ni‐MOL‐100) shows a much higher photocatalytic CO2‐to‐CO activity than the one exposing rich (010) crystal facets (Ni‐MOL‐010) and its bulky counterpart (bulky Ni‐MOF), with a catalytic activity up to 2.5 and 4.6 times more active than Ni‐MOL‐010 and bulky Ni‐MOF, respectively. Theoretical studies reveal that the two coordinatively unsaturated NiII ions with a close distance of 3.50 Å on the surface of Ni‐MOL‐100 enables synergistic catalysis, leading to more favorable energetics in CO2 reduction than that of Ni‐MOL‐010.
Crystal‐facet‐dependent catalytic performance for CO2 reduction has been observed in Ni‐based 2D MOLs. Ni‐MOL‐100 displays much higher catalytic activity than Ni‐MOL‐010, benefiting from the synergistic catalysis between two adjacent Ni sites in Ni‐MOL‐100.
The solar‐driven CO2 reduction is a challenge in the field of “artificial photosynthesis”, as most catalysts display low activity and selectivity for CO2 reduction in water‐containing reaction ...systems as a result of competitive proton reduction. Herein, we report a dinuclear heterometallic complex, CoZn(OH)L1(ClO4)3 (CoZn), which shows extremely high photocatalytic activity and selectivity for CO2 reduction in water/acetonitrile solution. It achieves a selectivity of 98 % for CO2‐to‐CO conversion, with TON and TOF values of 65000 and 1.8 s−1, respectively, 4, 19, and 45‐fold higher than the values of corresponding dinuclear homometallic CoCo(OH)L1(ClO4)3 (CoCo), ZnZn(OH)L1(ClO4)3 (ZnZn), and mononuclear CoL2(CH3CN)(ClO4)2 (Co), respectively, under the same conditions. The increased photocatalytic performance of CoZn is due to the enhanced dinuclear metal synergistic catalysis (DMSC) effect between ZnII and CoII, which dramatically lowers the activation barriers of both transition states of CO2 reduction.
In sync with zinc: A dinuclear heterometallic CoZn catalyst shows much higher photocatalytic activity than the corresponding dinuclear homometallic CoCo and ZnZn catalysts, or the mononuclear Co and Zn catalysts for CO2 reduction under the same conditions. The high performance of the CoZn catalyst is due to the enhanced dinuclear metal synergistic catalysis (DMSC) effect between ZnII and CoII.
Artificial synapses are the key building blocks for low‐power neuromorphic computing that can go beyond the constraints of von Neumann architecture. In comparison with two‐terminal memristors and ...three‐terminal transistors with filament‐formation and charge‐trapping mechanisms, emerging electrolyte‐gated transistors (EGTs) have been demonstrated as a promising candidate for neuromorphic applications due to their prominent analog switching performance. Here, a novel graphdiyne (GDY)/MoS2‐based EGT is proposed, where an ion‐storage layer (GDY) is adopted to EGTs for the first time. Benefitting from this Li‐ion‐storage layer, the GDY/MoS2‐based EGT features a robust stability (variation < 1% for over 2000 cycles), an ultralow energy consumption (50 aJ µm−2), and long retention characteristics (>104 s). In addition, a quasi‐linear conductance update with low noise (1.3%), an ultrahigh Gmax/Gmin ratio (103), and an ultralow readout conductance (<10 nS) have been demonstrated by this device, enabling the implementation of the neuromorphic computing with near‐ideal accuracies. Moreover, the non‐volatile characteristics of the GDY/MoS2‐based EGT enable it to demonstrate logic‐in‐memory functions, which can execute logic processing and store logic results in a single device. These results highlight the potential of the GDY/MoS2‐based EGT for next‐generation low‐power electronics beyond von Neumann architecture.
A novel graphdiyne (GDY)/MoS2‐based electrolyte‐gated transistor using GDY as a Li‐ion‐storage layer is proposed, which features robust stability and flexibility, an ultralow energy consumption, a long retention time, a quasi‐linear weight update with low noise, an ultrahigh Gmax/Gmin ratio, and an ultralow readout conductance. This GDY/MoS2‐based EGT has demonstrated its potential in applications of neuromorphic computing and in‐memory computing.
