Abstract
Artificial photosynthesis, light-driving CO
2
conversion into hydrocarbon fuels, is a promising strategy to synchronously overcome global warming and energy-supply issues. The quaternary ...AgInP
2
S
6
atomic layer with the thickness of ~ 0.70 nm were successfully synthesized through facile ultrasonic exfoliation of the corresponding bulk crystal. The sulfur defect engineering on this atomic layer through a H
2
O
2
etching treatment can excitingly change the CO
2
photoreduction reaction pathway to steer dominant generation of ethene with the yield-based selectivity reaching ~73% and the electron-based selectivity as high as ~89%. Both DFT calculation and
in-situ
FTIR spectra demonstrate that as the introduction of S vacancies in AgInP
2
S
6
causes the charge accumulation on the Ag atoms near the S vacancies, the exposed Ag sites can thus effectively capture the forming *CO molecules. It makes the catalyst surface enrich with key reaction intermediates to lower the C-C binding coupling barrier, which facilitates the production of ethene.
Unprecedented 30‐faceted BiVO4 polyhedra predominantly surrounded by {132}, {321}, and {121} high‐index facets are fabricated through the engineering of high‐index surfaces by a trace amount of Au ...nanoparticles. The growth of high‐index facets results in a 3–5 fold enhancement of O2 evolution from photocatalytic water splitting by the BiVO4 polyhedron, relative to its low‐index counterparts. Theory calculations reveal that water dissociation is more energetically favorable on the high‐index surfaces than on the low‐index (010), (110), and (101) surfaces, which is accompanied by a notable reduction in the overpotential (0.77–1.14 V) for the oxygen evolution reaction. The apparent quantum efficiency of O2 generation without an external electron supply reaches 18.3% under 430 nm light irradiation, which is an order of magnitude higher than that of the catalysts reported hitherto.
A 30‐faceted BiVO4 polyhedron predominantly surrounded by {132}, {321}, and {121} high‐index facets is synthesized. This BiVO4 polyhedron exhibits an enhanced O2 generation rate over that of low‐index counterparts, which originates from energetically favorable water dissociation and a notable reduction in the overpotential of the oxygen evolution reaction on the high‐index surfaces relative to that on the low‐index surfaces.
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•Design of crystal-facet exposed photocatalysts with various routes through altering the relative order of the surface energy.•Crystal facet-based surface junctions to promote the ...charge transfer and separation.•In situ techniques to detection of charge accumulation on crystal-faceted surfaces.•Exposed face-determined photocatalytic application from the point of the reactant adsorption and activation.
Tailoring semiconductor crystals with optimized reactive facets is considered one of effective strategies to improve photocatalytic activity and selectivity for energy conversion and environmental remediation. The arrangement of surface atom structure through crystal facet engineering could tune surface free energy, electronic band structure, charge transfer and separation, the reactant adsorption and product desorption, and surface redox sites. This progress report aims to concisely highlight recent state-of-the-art progress of crystal facet-dependent performance of promising photocatalysts beyond TiO2. It includes (1) design of crystal-facet exposed photocatalysts with various routes through altering the relative order of the surface energy; (2) crystal facet-based surface junctions to promote the charge transfer and separation; (3) in situ techniques to detection of charge accumulation on crystal-faceted surfaces; (4) exposed face-determined photocatalytic application in water splitting, photoreduction of CO2 into renewable fuels, degradation of organic contaminants from the point of the reactant adsorption and activation. The challenges and prospects for future development are also presented.
Highly ordered TiO2 nanotube arrays (TiO2NTs) evenly modified by Ni–Cu nanoparticles were successfully prepared by potential step method. Their morphologies, structures, and alloy composition were ...characterized by FESEM, XRD and EDS, respectively. The as-prepared Ni–Cu/TiO2NTs electrodes were employed for non-enzymatic glucose detection in alkaline electrolyte and showed better electro-catalytic activity compared with Ni/TiO2NTs and Cu/TiO2NTs electrodes. Factors that affected the electrocatalysis of the electrodes were examined and optimized. Consequently, a sensitive amperometric electrode of glucose was achieved under 0.6V vs. Ag/AgCl with a high sensitivity (1590.9μAmM−1cm−2), low detection limit (5μM) and wide linear range from 10μM to 3.2mM (R2=0.993). Furthermore, the oxidable species such as ascorbic acid and uric acid showed no significant interference in determination of glucose. The experiment results revealed a very good reproducibility and high stability for the proposed Ni–Cu/TiO2NTs electrodes.
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•Sandwich–like NiFe LDH/Co1-xS heterostructure has been successfully prepared.•The 3D catalytic space provides extra active sites over the original NiFe LDH.•The lattice mismatch of ...NiFe LDH induces the formation of lattice strain in Co1-xS.•The compressive strain possesses lower free energy in OER.•NiFe LDH/Co1-xS exhibits excellent long–term durability after 150 h test.
Sandwich–like NiFe layered double hydroxides/Co1-xS (NiFe LDH/Co1-xS) heterostructure with synergistic electrocatalytic effects for highly efficient oxygen evolution reaction is successfully prepared by electrodepositing Co1-xS on the surface of NiFe LDH grown on nickel foam (NF). The NF supported heterostructure possesses three-dimensional (3D) catalytic space and strained heterointerface. Thereinto the Co1-xS layer provides extra active sites over the original NiFe LDH. Besides, the lattice mismatch in the surface of NiFe LDH induces the formation of lattice strain in Co1-xS, which thus modulates the local electronic structures. Density functional theory (DFT) calculations validate that the strained heterointerface has advantageous OER activity. From the results of electrochemical tests, the NiFe LDH/Co1-xS possesses large number of active sites and fast charge transfer. More importantly, optimized structure and interface characteristics improve the electrocatalytic stability, resulting in long–term durability with almost no attenuation after 150 h constant current test.
WO3 homojunction film with integrated thermodynamic and kinetic advantages for solar water oxidation.
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•WO3 homojunction film was prepared by coupling an upper WO3(002) layer and a ...lower multi-crystal WO3 layer.•The WO3(002)/m-WO3 homojunction film shows good PEC water oxidation activity and stability.•The band position differences between WO3(002) and m-WO3 are thermodynamically favorable for charge separation and transfer.•The presence of WO3(002) on top has superior activity in the adsorption, activation and oxidation of water in kinetics.
The manipulation of the surface property of WO3 photoanode is the main breakthrough direction to improve its solar water oxidation performance both in thermodynamics and kinetics. Here, we report a WO3(002)/m-WO3 homojunction film that is composed of an upper WO3 layer with predominant (002) facet (WO3(002)) and a lower WO3 layer with multi-crystal facets (m-WO3) as a photoanode for solar water oxidation. Due to the synergistic effect of WO3(002) layer and m-WO3 layer, better water oxidation activity and stability are achieved on the WO3(002)/m-WO3 homojunction film relative to the m-WO3 and WO3(002) film. Specifically, the improved water oxidation performance on the WO3(002)/m-WO3 homojunction film is attributed to the followings. In thermodynamics, the band position differences between WO3(002) layer and m-WO3 layer lead to the formation of WO3(002)/m-WO3 homojunction, which has positive function of improving their charge separation and transfer. In kinetics, the upper WO3(002) layer of the WO3(002)/m-WO3 film has superior activity in the adsorption and activation of water molecules, water oxidation on this homojunction film photoanode is inclined to follow the four-holes pathway, and the corrosion of photoanode from the H2O2 intermediate is restrained. The present work provides a new strategy to modify the WO3 photoanodes for thermodynamically and kinetically efficient water oxidation.
A novel nonenzymatic glucose sensor was developed based on the Ni nanoparticles-loaded TiO2 nanotube arrays (Ni-NPs/TiO2NTs). The Ni-NPs/TiO2NTs nanocomposites were prepared first by anodization of ...Ti foil, followed by pulsed electrodeposition method (PED) and characterized by SEM, XRD and XPS respectively. The results showed that spherical Ni nanoparticles were well dispersed and embedded in the TiO2NTs. The electrochemical measurements presented that the activated Ni-NPs with a diameter of 40nm displayed high electrocatalytic activity for the oxidation of glucose and a good sensitivity of 700.2μA mM−1cm−2 at applied potential 0.6V, with detection limit of 2μM (S/N=3), and good linear range (from 0.004 to 4.8mM). Such high sensitivity was attributed to the large surface area of the highly dispersed nanoparticles for electrocatalytic reaction and the fast electron transfer in the TiO2NTs electrode. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of effective glucose nonenzymatic glucose sensor.
The development of efficient, recyclable, broad-spectrum photocatalysts was the primary objective in the field of photocatalytic wastewater degradation. Herein, a novel highly efficient ternary ...magnetic semiconductor composite was synthesized by integrating SrFe
12
O
19
, MoS
2
nanoflower clusters, and SnS
2
nanoflowers using high-temperature calcination and a one-step solvothermal method. The synthesized heterojunction nanocomposite was characterized using numerous analytical techniques, and its photocatalytic activity was evaluated under half sunlight intensity irradiation. The integration of SnS
2
with SrFe
12
O
19
and MoS
2
effectively modified the crystal structure and morphology of SnS
2
nanoflowers, leading to an increase in active sites while overcoming the significant electron–hole recombination rates of the individual components. The SrFe
12
O
19
/SnS
2
/MoS
2
composite achieved 98.69% degradation of MB dye at a suitable pH of 6 and a period of 120 min of irradiation. Additionally, it maintained an excellent magnetic phenomena which contributed to it effortless to collect and reclaim from the residual mixture. After three cycles, the MB dye degradation remained at 84.07%, demonstrating its endurance and resilience. The scavenger test identified the superoxide radical as the primary agent responsible for dye destruction. This work provides study presents a synthesis method for highly efficient photocatalysts using in natural visible-light that can be recovered by simply applying an external magnetic field.
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•FeB co-catalyst for Fe2O3 photoanode is first explored by a room-temperature dipping method.•FeB overlayer can effectively suppress carrier recombination and decrease interface ...resistance.•Fe2O3/FeB photoanode yields a photocurrent of 1.65mA/cm2 at 1.23Vvs. RHE and good photostability.•The proposed route can be used facilely for large-scale industrial production.
An unprecedented FeB-based co-catalyst for Fe2O3 nanorod photoanodes is explored for the first time by a simple room-temperature dipping method. The FeB overlayer formed in situ, which inherently possesses good interfacial contact, can remarkably suppress charge carrier recombination in Fe2O3 photoanodes and dramatically decrease electrode/electrolyte interface resistance. These beneficial features promote a twofold increment in photocurrent density and significantly reduce the onset potential of Fe2O3 photoanodes. Furthermore, their photoelectrochemical (PEC) performance can be further improved by co-loading of Co–Pi. The photocurrent density of 1.9mA/cm2 at 1.23V vs. RHE and the particularly low onset potential of 0.61V, which is dominantly smaller than those reported so far, can be realized controllably. Hence, our work suggests a new and promising co-catalyst for Fe2O3 photoanode. It also offers a facile strategy for fabricating low-cost and efficient PEC solar energy conversion devices.
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