An innovative MGM-BPNN-ARIMA model for China's energy consumption structure forecasting from the perspective of compositional data.

Effective forecasting of energy consumption structure is vital for China to reach its "dual carbon" objective. However, little attention has been paid to existing studies on the holistic nature and internal properties of energy consumption structure. Therefore, this paper incorporates the theory of compositional data into the study of energy consumption structure, which not only takes into account the specificity of the internal features of the structure, but also digs deeper into the relative information. Meanwhile, based on the minimization theory of squares of the Aitchison distance in the compositional data, a combined model based on the three single models, namely the metabolism grey model (MGM), back-propagation neural network (BPNN) model, and autoregressive integrated moving average (ARIMA) model, is structured in this paper. The forecast results of the energy consumption structure in 2023-2040 indicate that the future energy consumption structure of China will evolve towards a more diversified pattern, but the proportion of natural gas and non-fossil energy has yet to meet the policy goals set by the government. This paper not only suggests that compositional data from joint prediction models have a high applicability value in the energy sector, but also has some theoretical significance for adapting and improving the energy consumption structure in China.

Correction: State-of-the-art advancements of atomically thin two-dimensional photocatalysts for energy conversion.

Correction for 'State-of-the-art advancements of atomically thin two-dimensional photocatalysts for energy conversion' by Wa Gao et al., Chem. Commun., 2022, 58, 9594-9613, https://doi.org/10.1039/D2CC02708A.

State-of-the-art advancements of atomically thin two-dimensional photocatalysts for energy conversion.

Excessive use of fossil fuels leads to energy shortages and environmental pollution, threatening human health and social development. As a clean, green, and sustainable technology, generation of renewable energy from solar light through photocatalysis has received increasing attention to cope with the impending energy and environmental crisis. The atomically thin two-dimensional (2D) semiconductors with large surface area and abundant low-coordinate surface atoms prove to exhibit enormous potential to attain efficient photocatalytic performance. These 2D ultrathin materials can shorten the transport distance of charge carriers from the interior to the surface, enhance reactants' (e.g. CO2 and H2O) adsorption and activation to lower the energy barrier, promote specific reaction processes and inhibit competitive reactions, and regulate the efficiency and selectivity of the catalytic reaction. This Feature article provides a concise overview of the preparation, catalytic mechanism, strategies for boosting the photoconversion performance, various photocatalytic applications, and characterization techniques of atomically thin 2D semiconductors. The major challenges and opportunities of the ultrathin photocatalysts are also addressed. It is hoped that this review can provide useful guidelines toward further research on 2D nanocatalysts, and inspire practical applications of these unique materials for energy conversion.

Bismuth Vacancy-Induced Efficient CO2 Photoreduction in BiOCl Directly from Natural Air: A Progressive Step toward Photosynthesis in Nature.

Photocatalytic CO2 conversion into carbonaceous fuels through artificial photosynthesis is beneficial to global warming mitigation and renewable resource generation. However, a high cost is always required by special CO2-capturing devices for efficient artificial photosynthesis. For achieving highly efficient photocatalytic CO2 reduction (PCR) directly from natural air, we report rose-like BiOCl that is rich in Bi vacancies (VBi) assembled by nanosheets with almost fully exposed active {001} facets. These rose-like BiOCl with VBi assemblies provide considerable adsorption and catalytic sites, which hoists the CO2 capture and reduction capabilities, and thus expedites the PCR to a superior value of 21.99 µmol·g-1·h-1 CO generation under a 300 W Xe lamp within 5 h from natural air. The novel design and construction of a photocatalyst in this work could break through the conventional PCR system requiring compression and purification for CO2, dramatically reduce expenses, and open up new possibilities for the practical application of artificial photosynthesis.

Hollow InVO4 Nanocuboid Assemblies toward Promoting Photocatalytic N2 Conversion Performance.

The unique InVO4 mesocrystal superstructure, particularly with cubical skeleton and hollow interior, which consists of numerous nanocube building blocks, closely stacking by stacking, aligning by aligning, and sharing the same crystallographic orientations, is successfully fabricated. The synergy of a reaction-limited aggregation and an Ostwald ripening process is reasonably proposed for the growth of this unique superstructure. Both single-particle surface photovoltage and confocal fluorescence spectroscopy measurements demonstrate that the long-range ordered mesocrystal superstructures can significantly retard the recombination of electron-hole pairs through the creation of a new pathway for anisotropic electron flow along the inter-nanocubes. This promising charge mobility feature of the superstructure greatly contributes to the pronounced photocatalytic performance of the InVO4 mesocrystal toward fixation of N2 into NH3 with the quantum yield of 0.50% at wavelength of 385 nm.

Elegant Construction of ZnIn2S4/BiVO4 Hierarchical Heterostructures as Direct Z-Scheme Photocatalysts for Efficient CO2 Photoreduction.

The ZnIn2S4/BiVO4 heterostructures were elegantly designed through assembling ZnIn2S4 nanosheets onto the surface of BiVO4 decahedrons. This composite photocatalyst exhibits efficient photocatalytic conversion of CO2 into CO with a detectable amount of CH4 in the presence of water vapor. An electron spin-resonance spectroscopy (ESR) technique and density function theory (DFT) calculation affirm the direct Z-scheme structure in ZnIn2S4/BiVO4. The larger surface photovoltage (SPV) change and the longer liquid photoluminescence (PL) lifetime of the heterostructure, compared to the individual ZnIn2S4 and BiVO4 components, demonstrate that the Z-scheme structure can effectively promote the recombination of the photogenerated holes in the valence band (VB) of the ZnIn2S4 nanosheet with the electrons in the conduction band (CB) of the decahedral BiVO4 and lead to the abundant electrons surviving in the CB of ZnIn2S4 and holes in the VB of BiVO4, thus enhancing photocatalytic CO2 reduction performance. This study may make a potential contribution to the rational construction and deep understanding of the underlying mechanism of direct Z-schemes for advanced photocatalytic activity.

Anchoring of black phosphorus quantum dots onto WO3 nanowires to boost photocatalytic CO2 conversion into solar fuels.

A 0D-1D direct Z-scheme heterojunction consisting of black phosphorus quantum dots (BPQDs) anchored onto WO3 nanowires was well designed. Kelvin probe force microscopy studies provide direct evidence for charge transfer and separation between BPQDs and WO3 in a single nanowire, confirming the Z-scheme model. The BPQD-WO3 heterojunction displays excellent performance of photocatalytic reduction of CO2, exhibiting not only highly efficient carbon monoxide solar fuel conversion, but also a significant amount of ethylene (C2H4), a highly value-added hydrocarbon species, rarely reported in previous photocatalysis processes. Both experimental and theoretical calculations demonstrate that BPQD plays a critical role in photocatalytic formation of C2H4 from CO2.

Convincing Synthesis of Atomically Thin, Single-Crystalline InVO4 Sheets toward Promoting Highly Selective and Efficient Solar Conversion of CO2 into CO.

Atomically thin, single-crystalline InVO4 sheets with the uniform thickness of ∼1.5 nm were convincingly synthesized, which was identified with strong, low-angle X-ray diffraction peaks. The InVO4 atomic layer corresponding to 3 unit cells along [110] orientation exhibits highly selective and efficient photocatalytic conversion of CO2 into CO in the presence of water vapor. Surface potential change measurement and liquid photoluminescence decay spectra confirm that the atomically ultrathin structure can shorten the transfer distance of charge carriers from the interior onto the surface and decrease the recombination in body. It thus allows more electrons to survive and accumulate on the surface, which is beneficial for activation and reduction of CO2. In addition, exclusively exposed {110} facet of the InVO4 atomic layer was found to bind the generating CO weakly, facilitating quick desorption from the catalyst surface to form free CO molecules, which provides an ideal platform to catalytically selective CO product.

Flux synthesis of regular Bi4TaO8Cl square nanoplates exhibiting dominant exposure surfaces of {001} crystal facets for photocatalytic reduction of CO2 to methane.

Herein, orthorhombic regular Bi4TaO8Cl square nanoplates with an edge length of about 500 nm and a thickness of about 100 nm were successfully synthesized using a facile molten salt route. The as-prepared square nanoplates have been proven to be of {001} crystal facets as two dominantly exposed surfaces. The density functional theory calculation and photo-deposition of noble metal experiment demonstrate the electron and hole separation on different crystal facets and reveal that {001} crystal facets are in favor of the reduction reaction. Since the square nanoplate structure exhibits dominant exposure surfaces of the {001} facets, the molten salt route-based samples basically possess an obviously higher photocatalytic activity than those prepared by the solid state reaction (SSR) method. This study may provide inspiration for fabricating efficient photocatalysts.

Bi2 MoO6 Nanostrip Networks for Enhanced Visible-Light Photocatalytic Reduction of CO2 to CH4.

A three-dimensional Bi2 MoO6 nanostrip architecture was synthesized by the hydrothermal method using sodium oleate as a surfactant. The generated Bi2 MoO6 nanostrips intercross with each other to form a unique network structure with a band gap of 2.92 eV, corresponding to visible-light wavelength. Time-evolution experiments reveal the formation mechanism of the Bi2 MoO6 network. The photocatalytic reduction of CO2 to CH4 catalyzed by the Bi2 MoO6 architecture was evaluated and compared with the process catalyzed by a Bi2 MoO6 nanoplate analogue synthesized in the absence of sodium oleate as well as with the solid-state reaction. The Bi2 MoO6 nanostrips exhibit the best photocatalytic activity, which can be attributed to their high specific surface area, high light-absorption intensity, suitable thickness for fast charge-carrier migration, and the presence of pores for reactant transport.

Construction of an all-solid-state artificial Z-scheme system consisting of Bi2WO6/Au/CdS nanostructure for photocatalytic CO2 reduction into renewable hydrocarbon fuel.

An all-solid-state Bi2WO6/Au/CdS Z-scheme system was constructed for the photocatalytic reduction of CO2 into methane in the presence of water vapor. This Z-scheme consists of ultrathin Bi2WO6 nanoplates and CdS nanoparticles as photocatalysts, and a Au nanoparticle as a solid electron mediator offering a high speed charge transfer channel and leading to more efficient spatial separation of electron-hole pairs. The photo-generated electrons from the conduction band (CB) of Bi2WO6 transfer to the Au, and then release to the valence band (VB) of CdS to recombine with the holes of CdS. It allows the electrons remaining in the CB of CdS and holes in the VB of Bi2WO6 to possess strong reduction and oxidation powers, respectively, leading the Bi2WO6/Au/CdS to exhibit high photocatalytic reduction of CO2, relative to bare Bi2WO6, Bi2WO6/Au, and Bi2WO6/CdS. The depressed hole density on CdS also enhances the stability of the CdS against photocorrosion.

Construction and Nanoscale Detection of Interfacial Charge Transfer of Elegant Z-Scheme WO3/Au/In2S3 Nanowire Arrays.

Elegant Z-scheme WO3/Au/In2S3 nanowire arrays were precisely constructed through a facile step-by-step route. Surface potential change on pristine or In2S3-Au coated WO3 single nanowire under dark and illumination detected through a Kelvin probe force microscopy (KPFM) technique indicates that the vectorial holes transfer of In2S3 → Au → WO3 should occur upon the excitation of both WO3 and In2S3. In such charge transfer processes, the embedded Au nanoparticles in the heterojunction systems act as a charge mediator for electrons in the conduction band of WO3 and holes in the valence band of In2S3. The strong charge carrier separation ability of this structure will finally enhance the oxidation ability of WO3 with high concertation of photogenerated holes and, further, leave the free electrons in the In2S3 with long surviving time. Therefore, the unique Z-scheme WO3/Au/In2S3 heterostructure shows great visible-light activity toward photocatalytic reduction of CO2 in the presence of water vapor into renewable hydrocarbon fuel (methane: CH4).

Construction and Nanoscale Detection of Interfacial Charge Transfer of Elegant Z-Scheme WO3/Au/In2S3 Nanowire Arrays.

Elegant Z-scheme WO3/Au/In2S3 nanowire arrays were precisely constructed through a facile step-by-step route. Surface potential change on pristine or In2S3-Au coated WO3 single nanowire under dark and illumination detected through a Kelvin probe force microscopy (KPFM) technique indicates that the vectorial holes transfer of In2S3 → Au → WO3 should occur upon the excitation of both WO3 and In2S3. In such charge transfer processes, the embedded Au nanoparticles in the heterojunction systems act as a charge mediator for electrons in the conduction band of WO3 and holes in the valence band of In2S3. The strong charge carrier separation ability of this structure will finally enhance the oxidation ability of WO3 with high concertation of photogenerated holes and, further, leave the free electrons in the In2S3 with long surviving time. Therefore, the unique Z-scheme WO3/Au/In2S3 heterostructure shows great visible-light activity toward photocatalytic reduction of CO2 in the presence of water vapor into renewable hydrocarbon fuel (methane: CH4).