The
electrocatalytic reduction reaction of CO2 (CO2RR) is a promising strategy to promote the global carbon balance
and combat global climate change. Herein, exclusive Bi-N4 sites on porous carbon networks can be achieved through thermal
decomposition of a bismuth-based metal–organic framework (Bi-MOF)
and dicyandiamide (DCD) for CO2RR. Interestingly,
in situ environmental transmission electron microscopy (ETEM) analysis
not only directly shows the reduction from Bi-MOF into Bi nanoparticles
(NPs) but also exhibits subsequent atomization of Bi NPs assisted
by the NH3 released from the decomposition of DCD. Our
catalyst exhibits high intrinsic CO2 reduction activity
for CO conversion, with a high Faradaic efficiency (FECO up to 97%) and high turnover frequency of 5535 h–1 at a low overpotential of 0.39 V versus reversible hydrogen
electrode. Further experiments and density functional theory results
demonstrate that the single-atom Bi-N4 site is the dominating
active center simultaneously for CO2 activation and the
rapid formation of key intermediate COOH* with a low free energy barrier.
Manipulating the coordination environment of the active center via anion modulation to reveal tailored activity and selectivity has been widely achieved, especially for carbon-based single-atom site catalysts (SACs). However, tuning ligand fields of the active center by single-site metal cation regulation and identifying the effects on the resulting electronic configuration is seldom explored. Herein, we propose a single-site Ru cation coordination strategy to engineer the electronic properties by constructing a Ru/LiCoO 2 SAC with atomically dispersed RuÀ Co pair sites. Benefitting from the strong electronic coupling between Ru and Co sites, the catalyst possesses an enhanced electrical conductivity and achieves near-optimal oxygen adsorption energies. Therefore, the optimized catalyst delivers superior oxygen evolution reaction (OER) activity with low overpotential, the high mass activity of 1000 A g oxide À 1 at a small overpotential of 335 mV, and excellent long-term stability. It also exhibits rapid kinetics with superior rate capability and outstanding durability in a zinc-air battery.
The in‐depth understanding of local atomic environment–property relationships of p‐block metal single‐atom catalysts toward the 2 e− oxygen reduction reaction (ORR) has rarely been reported. Here, guided by first‐principles calculations, we develop a heteroatom‐modified In‐based metal–organic framework‐assisted approach to accurately synthesize an optimal catalyst, in which single In atoms are anchored by combined N,S‐dual first coordination and B second coordination supported by the hollow carbon rods (In SAs/NSBC). The In SAs/NSBC catalyst exhibits a high H2O2 selectivity of above 95 % in a wide range of pH. Furthermore, the In SAs/NSBC‐modified natural air diffusion electrode exhibits an unprecedented production rate of 6.49 mol peroxide gcatalyst−1 h−1 in 0.1 M KOH electrolyte and 6.71 mol peroxide gcatalyst−1 h−1 in 0.1 M PBS electrolyte. This strategy enables the design of next‐generation high‐performance single‐atom materials, and provides practical guidance for H2O2 electrosynthesis.
in such areas. [2] The ideal efficiency of solar energy conversion of plasmonic metalbased hybrid catalysts comes from anisotropic crystallization, heterointerface. [3] Besides the morphology of plasmonic metal nanocrystals (NCs), the solar energy conversion efficiency of plasmonic metalsemiconductor NCs should be sensitive to the manner of coupling between metal NCs and the semiconductor. [4] Therefore, it is highly desirable to explore a versatile strategy to synthesize accurately controlled anisotropic configuration, monocrystalline shell, and intended site-selective heterocontact between plasmonic metal and semiconductor.The absorbance range is an essential factor on the efficiency of light harvesting and photoelectric catalysis. So far, most of the applications based on plasmonic metal hybrid NCs are limited in specific spectral range, because most of plasmonic metal nanostructures only have plasmon resonances in the visible regions. [5] Au nanorods (NRs), [6] because of its intriguing longitudinal surface plasmon resonance (LSPR), can be excited by incident light polarized along the axial direction. Therefore, it can be synthetically tailored across a broad spectral range and In this communication, light harvesting and photoelectrochemical (PEC) hydrogen generation beyond the visible region are realized by an anisotropic plasmonic metal/semiconductor hybrid photocatalyst with precise control of their topology and heterointerface. Controlling the intended configuration of the photocatalytic semiconductor to anisotropic Au nanorods' plasmonic hot spots, through a water phase cation exchange strategy, the site-selective overgrowth of a CdSe shell evolving from a core/shell to a nanodumbbell is realized successfully. Using this strategy, tip-preferred efficient photoinduced electron/hole separation and plasmon enhancement can be realized. Thus, the PEC hydrogen generation activity of the Au/CdSe nanodumbbell is 45.29 µmol cm −2 h −1 (nearly 4 times than the core/shell structure) beyond vis (λ > 700 nm) illumination and exhibits a high faradic efficiency of 96% and excellent stability with a constant photocurrent for 5 days. Using surface photovoltage microscopy, it is further demonstrated that the efficient plasmonic hot charge spatial separation, which hot electrons can inject into CdSe semiconductors, leads to excellent performance in the Au/CdSe nanodumbbell.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/aenm.201803889.Including the visible light (400-700 nm), the light harvest beyond visible (λ > 700 nm with ≈43% ratio of solar energy) to contribute effective photocatalysis is important but rarely studied. [1] Plasmonic metal based anisotropic metal-semiconductor hybrid nanostructures emerge to be potential materials for applications
The
renewable energy-powered electrolytic reduction of carbon dioxide
(CO2) to methane (CH4) using water as a reaction
medium is one of the most promising paths to store intermittent renewable
energy and address global energy and sustainability problems. However,
the role of water in the electrolyte is often overlooked. In particular,
the slow water dissociation kinetics limits the proton-feeding rate,
which severely damages the selectivity and activity of the methanation
process involving multiple electrons and protons transfer. Here, we
present a novel tandem catalyst comprising Ir single-atom (Ir1)-doped hybrid Cu3N/Cu2O multisite that
operates efficiently in converting CO2 to CH4. Experimental and theoretical calculation results reveal that the
Ir1 facilitates water dissociation into proton and feeds
to the hybrid Cu3N/Cu2O sites for the *CO protonation
pathway toward *CHO. The catalyst displays a high Faradaic efficiency
of 75% for CH4 with a current density of 320 mA cm–2 in the flow cell. This work provides a promising
strategy for the rational design of high-efficiency multisite catalytic
systems.
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