Weak Adsorption Research Articles

Enhancing photocatalytic H2O2 production with Au co-catalysts through electronic structure modification

Gold-based co-catalysts are a promising class of materials with potential applications in photocatalytic H2O2 production. However, current approaches with Au co-catalysts show limited H2O2 production due to intrinsically weak O2 adsorption at the Au site. We report an approach to strengthen O2 adsorption at Au sites, and to improve H2O2 production, through the formation of electron-deficient Auδ+ sites by modifying the electronic structure. In this case, we report the synthesis of TiO2/MoSx-Au, following selective deposition of Au onto a MoSx surface which is then further anchored onto TiO2. We further show that the catalyst achieves a significantly increased H2O2 production rate of 30.44 mmol g−1 h−1 in O2-saturated solution containing ethanol. Density functional theory calculations and X-ray photoelectron spectroscopy analysis reveal that the MoSx mediator induces the formation of electron-deficient Auδ+ sites thereby decreasing the antibonding-orbital occupancy of Au-Oads and subsequently enhancing O2 adsorption. This strategy may be useful for rationally designing the electronic structure of catalyst surfaces to facilitate artificial photosynthesis.

3D Ternary Alloy Artificial Interphase Toward Ultra‐Stable and Dendrite‐Free Aqueous Zinc Batteries

AbstractRechargeable aqueous zinc‐ion batteries (AZIBs) are one of the most promising post‐lithium battery technologies due to their low cost, high safety, and environmental friendliness. However, their practical development is hindered by the issues of Zn metal anodes, including dendrite growth, passivation, hydrogen evolution and other side reactions. Herein, to circumvent these issues, a facile and universal alloy electrodeposition strategy is proposed to construct a 3D structured ternary Zn alloy artificial interphase layer on Zn foil as an anode for high‐performance AZIBs. The density functional theory (DFT) theoretical calculations, in situ optical visualization and spectroscopic results validate that the zincophilic Zn─Sn─Bi@Zn ternary alloy anode with lower migration energy barrier and weak hydrogen adsorption sites can promote the uniform Zn deposition and suppress hydrogen evolution reactions. The Zn─Sn─Bi@Zn//NH4V4O10 full cell demonstrates a high specific capacity 110.4 mAh g−1 even after 10 000 cycles at 5.0 A g−1. Notably, the full cell with a high NH4V4O10 cathode loading mass of ≈20.0 mg cm−2 maintains cyclic stability for 400 cycles. This work proposes an innovative Zn‐based ternary alloy anode methodology as a design strategy for advanced AZIBs and beyond.

Mechanistic exploration in controlling the product selectivity via metals in TiO2 for photocatalytic carbon dioxide reduction

Harnessing the power of the sun, the photocatalytic CO2 reduction process emerges as a pivotal sustainable solution, utilizing solar energy a premier, clean energy source known for its efficiency and economic viability in the current energy paradigm. This study investigates the impact of metals (Cu, Ag, Au) on enhancing the photocatalytic CO2 reduction capabilities of TiO2. In-depth mechanistic analysis conducted using in-situ DRIFTS for identifying the key reaction intermediates, highlights that the catalytic performance, both in terms of activity and product selectivity, is tightly linked to the underlying reaction mechanisms route, optoelectronic properties, and substrate’s (CO2 and H2O) affinities to the catalyst surface. Enhanced light absorption and reduced charge recombination (lifetime enhancement from 0.21 ns to ∼1.2 ns) in case of metal incorporated resulted in enhanced overall photocatalytic performance. With Au as dopant, demonstrated highest electron selectivity for H2 (>97%) compared to Ag and Cu, which showed relatively higher CO2 reduction electron selectivity (∼20% for Cu). The study reveals the crucial interplay of intermediate stabilization, demonstrating its critical role in governing the reaction pathways i.e., carbene or formaldehyde routes as observed in case of Ag and Cu respectively and thus the specific final products. For enhancing the selectivity of CO, engineering the catalyst surface to favour weak CO adsorption is vital. Observations in the CO-TPD measurements demonstrated that Ag sites were effective in promoting the weaker CO* stabilization thus displayed more selectivity towards CO as compared to Cu. While higher CH3OH formation rates in case of Cu, were found to be related to the augmented reactive M=O species stabilization which promotes the oxidation of CH4 to CH3OH. Additionally, in case of Cu, the CH3O* intermediates stabilized effectively, which contributed to more Methanol selectivity through favoured formaldehyde route. While in case of Ag, the CH2* stabilization suggests more probability of the carbene pathway in comparison to the formaldehyde route (as in case of Cu) for producing the CH4 as the final hydrogenated C1 product. These insights guide the strategic design of catalysts for controlling the reaction pathways and thus selective C1 product production in photocatalytic CO2 reduction, offering insights for advanced catalyst design.

Insight into adsorption properties and mechanism of geopolymer adsorbents with inherent alkali release for tetracycline

The crux to practical application of geopolymer adsorbents for antibiotics that are easily protonated and deprotonated is to clarify the dynamic adsorption mechanism of geopolymer with intrinsic alkaline release. The adsorption properties, adsorption mechanism, adsorption-desorption cycle and waste adsorbent regeneration based on the geopolymer adsorbent for adsorbing tetracycline under the spontaneous dynamic pH conditions were systematically investigated by experiment, characterization and density functional theory. The results confirmed that the structures of tetracycline depended on dynamic pHs of adsorption systems changed by geopolymer adsorbent. The electrostatic interaction assisted by hydrogen-bonding and n-π interaction dominated the adsorption process when the dynamic pHs were less than 7. And the hydrogen-bonding and n-π interaction provided the possibility of weak adsorption effect in highly alkaline environments. The geopolymer powder exhibited outstanding adsorption efficiency (∼95.62%, 30 min) due to the strong electrostatic adsorption between electronegative skeleton of geopolymer and zwitterions species tetracycline under dynamic pH range of 4–6.3 and fitted the pseudo-second-order model. The outstanding competitive adsorption properties in NaCl solution, adsorption (4 times)-desorption (3 times) cycle properties and regenerative property of waste adsorbent were exhibited. The mechanism study based on the dynamic pHs which is closer to actual conditions can provide important reference for practical application of easy preparation and low cost geopolymer adsorbents.

Pd/NiMoO4/NF electrocatalysts for the efficient and ultra-stable synthesis and electrolyte-assisted extraction of glycolate

Electrocatalytic conversion of organic small molecules is a promising technique for value-added chemical productions but suffers from high precious metal consumption, poor stability of electrocatalysts and tedious product separation. Here, a Pd/NiMoO4/NF electrocatalyst with much lowered Pd loading amount (3.5 wt.%) has been developed for efficient, economic, and ultra-stable glycolate synthesis, which shows high Faradaic efficiency (98.9%), yield (98.8%), and ultrahigh stability (1500 h) towards electrocatalytic ethylene glycol oxidation. Moreover, the obtained glycolic acid has been converted to value-added sodium glycolate by in-situ acid-base reaction in the NaOH electrolyte, which is atomic efficient and needs no additional acid addition for product separation. Moreover, the weak adsorption of sodium glycolate on the catalyst surface plays a significant role in avoiding excessive oxidation and achieving high selectivity. This work may provide instructions for the electrocatalyst design as well as product separation for the electrocatalytic conversions of alcohols.

Niobium doped MoS2 with double S vacancy defects as gas sensing materials for sulfur-containing gas molecules: A first-principle investigation

Electronic and adsorption properties of MoS2 with single S vacancy (MoS2 (VS)) and double S vacancy defects (MoS2 (V2S)) toward three gas molecules (SO2, H2S and SO3) are studied based on the density functional theory (DFT). The adsorption energy, energy band, density of states (DOS), charge density difference (CDD), highest occupied molecule orbital/lowest unoccupied molecule orbital (HOMO/LUMO) and work function are calculated. The results indicate that pristine MoS2 is not suitable for high-sensitivity sensing detection for SO2, H2S and SO3, which exhibits weak adsorption forces. At the same time, MoS2 (VS) and MoS2 (V2S) are still physical adsorption for three gas molecules. Therefore, the synergistic effect of double S vacancies and Nb doping on the adsorption characteristics of MoS2 is studied. The results show that the adsorption type of both MoS2 (V2S)/2Nb and MoS2 (V2S)/3Nb for H2S is changed from physical adsorption to chemical adsorption. The corresponding physical mechanism is discussed.

Amorphous/Crystalline Phases Mixed Nanosheets Array Rich in Oxygen Vacancies Boost Oxygen Evolution Reaction of Spinel Oxides in Alkaline Media.

As promising oxygen evolution reaction (OER) catalysts, spinel-type oxides face the bottleneck of weak adsorption for oxygen-containing intermediates, so it is challenging to make a further breakthrough in remarkably lowering the OER overpotential. In this study, a novel strategy is proposed to substantially enhance the OER activity of spinel oxides based on amorphous/crystalline phases mixed spinel FeNi2O4 nanosheets array, enriched with oxygen vacancies, in situ grown on a nickel foam (NF). This unique architecture is achieved through a one-step millisecond laser direct writing method. The presence of amorphous phases with abundant oxygen vacancies significantly enhances the adsorption of oxygen-containing intermediates and changes the rate-determining step from OH*→O* to O*→OOH*, which greatly reduces the thermodynamic energy barrier. Moreover, the crystalline phase interweaving with amorphous domains serves as a conductive shortcut to facilitate rapid electron transfer from active sites in the amorphous domain to NF, guaranteeing fast OER kinetics. Such an anodic electrode exhibits a nearly ten fold enhancement in OER intrinsic activity compared to the pristine counterpart. Remarkably, it demonstrates record-low overpotentials of 246 and 315 mV at 50 and 500 mA cm-2 in 1 m KOH with superior long-term stability, outperforming other NiFe-based spinel oxides catalysts.

Cobalt catalysts for COx-free hydrogen production: Effect of catalyst type on ammonia decomposition in gliding discharge plasma reactor

Hydrogen is considered the cleanest, most environmentally friendly fuel and energy carrier required for the gradual decarbonisation of many industrial sectors. Using ammonia as a Cox-free source of hydrogen is the most reasonable and most applicable method. This paper studies the properties and activity of cobalt catalysts in the ammonia decomposition reaction using a plasma-catalytic system. The effect of catalyst type (supported versus bulk) was evaluated. The catalysts were examined using XRD, STEM-EDX, and sorption techniques (N2 physisorption, TGA-TPR, H2-TPD, CO2-TPD) to reveal the influence of physicochemical properties of these two types of catalysts on the efficiency of NH3 decomposition in the plasma-catalytic process using a gliding discharge plasma. The results disclose that the supported-type catalyst (Ba-Co/CeO2) decomposed NH3 more effectively than the bulk-type catalyst (Co/Ce/Ba). At discharge power of 300 W and flow rate of 180 dm3 h–1 of NH3:N2 mixture (50/50 vol%), the ammonia conversion over the Ba-Co/CeO2 catalyst was 70%, whereas over the Co/Ce/Ba catalyst it was only 21%. The favourable performance of the supported-type catalyst was attributed to a more thermally stable surface area compared with the bulk-type catalyst. Smaller and more stable cobalt nanoparticles (NPs) with numerous weak hydrogen adsorption sites were also seen. Meanwhile, the strong basic sites were generated, improving the electron-donating ability of the surface active sites. High ammonia conversion and relatively low-energy consumption of the plasma-catalytic ammonia decomposition over Ba-Co/CeO2 make it suitable for practical hydrogen production applications, such as fuel cells and hydrogen storage.

Calculation of hydrogen adsorption isotherms and Henry coefficients with mixed CO2 and CH4 gases on hydroxylated quartz surface: Implications to hydrogen geo-storage

Hydrogen is a clean fuel that is becoming increasingly popular in addressing future energy challenges, however, its viable storage requires an understanding of its interaction with underground rock minerals. For this purpose, this study focuses on developing adsorption isotherms and Henry coefficients for hydrogen in hydroxylated quartz surfaces, which are predominant in sandstone and shale rocks. In this study, a molecular-scale hydroxylated quartz structure with a pore space is generated and the Monte Carlo (MC) simulation is utilized to assess the adsorption isotherms and Henry coefficients. Initially, the CO2 adsorption with the hydroxylated quartz is matched with the published data to determine the accuracy of MC simulation and the mineral-fluid interaction. After that, the concentration of H2 within the pore is progressively increased and the competitive adsorption is calculated under various subsurface temperature and pressure conditions. Additionally, CH4 is introduced to understand the competitive adsorption dynamics between H2 and CH4. The findings indicate that increasing pressure results in increasing molecules of hydrogen that monotonically increase H2 adsorption. On the contrary, increasing temperature reduces the affinity of hydrogen with the quartz surface causing a decrease in adsorption capacity and Henry coefficients. Furthermore, a weak single hydrogen adsorption layer is developed at all pressure and temperature conditions, while most of the hydrogen remains as a free gas in the pore. In addition, the hydroxyl group controls most of the adsorption of hydrogen in the hydroxylated quartz. Furthermore, the addition of water film (approximately 1 wt%) reduces the hydrogen adsorption by around 3 %. The H2 adsorption values further experience a notable decrease with the introduction of CO2 and CH4, primarily due to the establishment of a strong adsorption layer caused by the high electrostatic attraction between these gases and the quartz mineral. The study offers crucial microscopic details regarding H2 adsorption alongside CO2 and CH4 gases within hydroxylated quartz pores. These insights support efficient hydrogen geo-storage and larger-scale simulation research.

An Adaptable Charge Source Enabled by Mode‐Switchable TENG for Efficient Self‐Repairing Coating

AbstractSelf‐repairing coatings have received widespread attention due to their ability to repair damaged surfaces. However, film‐forming molecules can only be fixed on the metal surface through relatively weak physical and chemical adsorption. This drawback limits its self‐repairing ability. Here, a mode‐switchable TENG (MS‐TENG) is developed, which has the ability to switch between AC and DC outputs as an adjustable charge source for self‐repairing coatings. Besides the normal sector electrodes of rotational TENG, MS‐TENG has a special design of external electrodes (small extension electrodes on rotator and inner/outer orbit electrodes on stator) and achieves charge accumulation through an excitation circuit and DC output through air breakdown on external electrodes with advantage of the complete release of accumulated charges. Compared with traditional air breakdown TENG, its current output has been improved. In addition, the air breakdown process occurs in the external electrode framework independent of the TENG body. Therefore, the negative impact of air breakdown is suppressed. Finally, MS‐TENG is used to achieve rapid electrostatic adsorption of charged film‐forming molecules through charge injection. MS‐TENG as a charge source effectively improves the performance of self‐repairing coatings, with a corrosion inhibition rate of 96.9%.

Regulation of TiO2/ZSM-5 catalyst for enhanced photocatalytic toluene oxidation: Intensified light absorption, charge separation and toluene adsorption

TiO2 has been widely studied in photocatalytic VOCs oxidation but its photocatalytic activity is still unsatisfied due to poor visible light absorption, serious charge recombination and weak toluene adsorption. Herein, a composite catalyst (TiO2/ZSM-5) was constructed between TiO2 and hierarchical ZSM-5 by ball milling for photocatalytic toluene oxidation. The optimal composite catalyst exhibited the toluene degradation efficiency of 91.08 %, which was 2.7 and 1.3 times than those of TiO2 and TiO2/commercial ZSM-5. It showed that the strong interaction between TiO2 and hierarchical ZSM-5 was established via the formation of Ti-O-Si bond, which decreased the band gap from 3.08 to 0.55 eV when compared with TiO2 and was helpful for the enhanced charge separation. In addition, the mesoporous volume of hierarchical ZSM-5 was regulated by a dual-template method, making the mesoporous volume increased from 0.23 to 0.38 cm−3 g−1 when compared with TiO2/commercial ZSM-5, which improved the toluene adsorption capacity from 0.12 to 0.16 cm−3 g−1. DFT calculation further indicated that the energy barrier of toluene oxidation and ring-opening reaction was reduced in the presence of hierarchical ZSM-5. This work provided a new catalyst design method to improve the photocatalytic activity by the synergy action of TiO2 and ZSM-5.

Computational investigation of charge injection into modified graphdiyne nanosheet via Al doping and Li decoration to improve hydrogen adsorption

The utilization of hydrogen as a clean fuel has been made feasible by the expanding development of cutting-edge materials for hydrogen adsorption and storage. In this study, we thoroughly assessed hydrogen storage capability on both neutral and charge-injected graphdiyne (GDY) nanosheets modified with Al doping and Li decorating (Li.Al-GDY). According to the findings, pure GDY has an adsorption energy of −0.093 eV, while GDY modified with Al and Li atoms has an improved adsorption energy of −0.577 eV. The highest H2 adsorption energy of −0.760 eV was calculated for the applied charge of −2 e to the Li.Al-GDY nanosheet, indicating a significant enhancement in the adsorption energy with the charge injection. While the pristine GDY nanosheet serves as a very poor H2 molecule adsorber and cannot even hold one H2 molecule, the charged Li.Al-GDY nanosheet maintains 13 H2 molecules with an average adsorption energy of −0.287 eV. According to the results, injecting charge into the nanosheet along with modification techniques such as doping and decorating can significantly boost the effectiveness of weak carbon adsorbents in terms of hydrogen adsorption. Such approaches enable the realization of the goal of using carbon adsorbents as H2 green fuel storage.

Flotation Separation of Magnesite from Dolomite Using Sodium Silicate Modified with Zinc Sulfate as a Selective Depressant

Flotation separation of magnesite from dolomite in the presence of SSZS (sodium silicate modified with zinc sulfate) as an inhibitor and NaOL (sodium oleate) as a collector has been studied via flotation tests, zeta potential measurements, contact angle measurements, and Fourier transformation infrared spectroscopy analysis (FT-IR). The flotation tests show that NaOL has strong collecting capacity in magnesite and dolomite flotation, so it is difficult to separate two minerals via flotation without inhibitors. SSZS is used as the depressant, which can selectively inhibit dolomite flotation and has little depression effect on magnesite. Zeta potential measurements, contact angle measurements, and FT-IR analysis indicate that SSZS can adsorb strongly onto dolomite’s surface and has a weak adsorption effect on magnesite. The adsorption of SSZS prevents NaOL from acting on the surface of dolomite. On the contrary, because there is little adsorption of SSZS onto magnesite, NaOL can still adsorb onto magnesite’s surface.

Exceptional Performance of 3D Additive Manufactured NiFe Phosphite Oxyhydroxide Hollow Tubular Lattice Plastic Electrode for Large‐Current‐Density Water Oxidization

In this article, we report a 3D NiFe phosphite oxyhydroxide plastic electrode using high‐resolution digital light processing (DLP) 3D‐printing technology via induced chemical deposition method. The as‐prepared 3D plastic electrode exhibits no template requirement, freedom design, low‐cost, robust, anticorrosion, lightweight, and micro‐nano porous characteristics. It can be drawn to the conclusion that highly oriented open‐porous 3D geometry structure will be beneficial for improving surface catalytic active area, wetting performance, and reaction–diffusion dynamics of plastic electrodes for oxygen evolution reaction (OER) catalysis process. Density functional theory (DFT) calculation interprets the origin of high activity of NiFe(PO3)O(OH) and demonstrates that the implantation of the –PO3 can effectively bind the 3d orbital of Ni in NiFe(PO3)O(OH), lead to the weak adsorption of intermediate, make electron more active to improve the conductivity, thereby lowing the transform free energy of *O to *OOH. The water oxidization performance of as‐prepared 3D NiFe(PO3)O(OH) hollow tubular (HT) lattice plastic electrode has almost reached the state‐of‐the‐art level compared with the as‐reported large‐current‐density catalysts or 3D additive manufactured plastic/metal‐based electrodes, especially for high current OER electrodes. This work breaks through the bottleneck that plagues the performance improvement of low‐cost high‐current electrodes.

VBF MBenes as promising gas sensor and adsorbent toward CO, CO2, NO, and NO2

MBenes have attracted wide interest because of their potential value the materials, chemistry, and physics domains. In this study, we investigated an VBF material, a member of the MBene family, for gas-sensing applications. The adsorption behavior of CO, CO2, NO, and NO2 molecules on perfect and transition metals (TM; Mn, Fe, Co, Ni)-doped VBF structures was examined using density-functional theory (DFT) calculations. The calculation results indicated that the pristine VBF structure has a weak adsorption capacity toward CO, CO2, NO, and NO2. Thus, introducing TM impurities significantly improved the sensitivity of the VBF substrate to CO, NO, and NO2 gases. Electron localization function (ELF) diagrams showed that the adsorption behaviors at this point are chemisorption. Moreover, the I-V curves showed that the Mn-doped VBF has a good sensitivity to the adsorption of NO molecules. The good sensitivity, suitable recovery time, and high stability indicate that the Mn-doped VBF is an ideal reusable gas sensor for NO molecules. In addition, after seven NO molecules were adsorbed on VBF-Fe and VBF-Co substrates, the systems still maintained a good adsorption capacity. Thus, Fe- and Co-doped VBF can be used to capture the toxic NO gas.

Flotation Separation of Cassiterite from Calcite Using Low-Molecular-Weight Citrus Pectin as Depressant

This paper presents the development of an environmentally friendly, small molecular depressant citrus pectin for improving the recovery of cassiterite resources. Citrus pectin extracted from citrus peel was utilized as the depressant, and it demonstrated significant potential in separating calcite from cassiterite in micro-flotation tests. The molecular weight of the citrus pectin extracted in this paper decreased from 11,485,412 Da to 32,959 Da compared to commercial pectin, resulting in the depressant efficiency of the reagent. The results of a zeta potential and adsorption test indicated that citrus pectin had less and weaker adsorption on the cassiterite surface and could be replaced with NaOL. The chemical adsorption process of citrus pectin on the surface of calcite was determined through FTIR spectroscopy analysis. XPS analysis results indicated that the interaction between the carboxyl groups of citrus pectin and calcium atoms enables adsorption to occur. The AFM revealed that citrus pectin displayed a uniform and dense pattern of point-like adsorption on the surface of calcite. Micro-flotation experiments showed that cassiterite recovery of 80% can be obtained at a citrus pectin dosage of 10 mg/L. Citrus pectin has the advantages of being low-cost, highly selective, and environmentally suitable, making it a promising alternative to conventional reagents.

Mechanistic Insights into the Discharge Processes of Li-CO2 Batteries.

Li-CO2 batteries facilitate renewable energy storage in a cost-effective, eco-friendly manner. However, an inadequate understanding of their reaction mechanism severely impedes their development. Here we outline recent mechanistic advances in the discharge processes of Li-CO2 batteries, particularly in terms of the theoretical aspect. First, the vital factors affecting the formation of discharge intermediates are highlighted, and a surface lithiation mechanism predominantly applicable to catalysts with weak CO2 adsorption is proposed. Subsequently, the modeling of the chemical potential of Li++e-, which is crucial for the evaluation of the theoretical limiting voltage, is detailed. Finally, challenges and future directions pertaining to the further development of Li-CO2 are discussed. In essence, this concept article seeks to inspire future experimental and theoretical studies in advancing the development of Li-CO2 electrochemical technology.

DFT Study of Metal (Ag, Au, Pt)-Modified SnS2 for Adsorption of SF6 Decomposition Gases in Gas-Insulated Switchgear.

In this study, the gas-sensitive response of metal (Ag, Au, Pt)-modified SnS2 toward SF6 decomposition gases (SOF2, SO2F2, SO2, H2S) in gas-insulated switchgear was studied by analyzing the adsorption structure, band structure, charge transfer, and density of states based on density functional theory. The results show that the adsorption of the four target gases on pristine SnS2 belongs to weak physical adsorption. Compared with the pristine SnS2, the adsorption energy of the transition metal atom-modified SnS2 monolayer has been improved to a certain extent and the adsorption capacity of these four gases on the transition metal atom-modified SnS2 monolayer has obviously improved. Moreover, the recovery time of Ag-SnS2/SOF2, Ag-SnS2/SO2F2, Au-SnS2/SOF2, Au-SnS2/SO2F2, and Pt-SnS2/SO2F2 is too short, indicating that these conditions have poor adsorption capacity and sensitivity to SF6 decomposition gases and are not suitable as detection materials for these gases. According to the different changes in conductivity during adsorption, it provides a feasible solution to detect each SF6 decomposition gas. This theoretical study effectively explained the adsorption and sensing properties between the metal-modified monolayers and gases.

Manipulating electronic structure of nickel phosphide via asymmetric coordination interaction for anion-exchange membrane based seawater electrolysis

Alkaline seawater electrolysis faces serious problems such as low catalytic activity of bifunctional catalysts and vulnerability to Cl- corrosion. Hence, Ru-doped nickel phosphide asymmetric structure (Ru-Ni2P/Ni5P4) has been synthesized as highly efficient and corrosion resistant electrocatalysts for alkaline seawater electrolysis at high current density. In-situ characterization technique and DFT calculations reveal that compared with the monophase nickel phosphide, the construction of NixP asymmetric structure manipulate the electronic structure and d-band center, promoting the adsorption of intermediates, as well as accelerate phase transition of the OER process. Moreover, the weak adsorption energy of Cl- on the surface of the Ru-Ni2P/Ni5P4 catalyst avoids the corrosion of Cl- in seawater. Consequently, Ru-Ni2P/Ni5P4 achieve 1000 mA cm−2 with overpotentials of only 128 and 450 mV for HER and OER, respectively. After assembling the Anion-exchange-membrane water electrolyzer (AEMWE), Ru-Ni2P/Ni5P4 shows high average efficiency and economic value at different current densities, and demonstrates its corrosion resistance to Cl- and potential for industrial applications.

Construction of Ag─Co(OH)2 Tandem Heterogeneous Electrocatalyst Induced Aldehyde Oxidation and the Co-Activation of Reactants for Biomass Effective and Multi-Selective Upgrading.

The electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) provides a feasible way for utilization of biomass resources. However, how to regulate the selective synthesis of multiple value-added products is still a great challenge. The cobalt-based compound is a promising catalyst due to its direct and indirect oxidation properties, but its weak adsorption capacity restricts its further development. Herein, by constructing Ag─Co(OH)2 heterogeneous catalyst, the efficient and selective synthesis of 5-hydroxymethyl-2-furanoic acid (HMFCA) and 2,5-furan dicarboxylic acid (FDCA) at different potential ranges are realized. Based on various physical characterizations, electrochemical measurements, and density functional theory calculations, it is proved that the addition of Ag can effectively promote the oxidation of aldehyde group to a carboxyl group, and then generate HMFCA at low potential. Moreover, the introduction of Ag can activate cobalt-based compounds, thus strengthening the adsorption of organic molecules and OH- species, and promoting the formation of FDCA. This work achieves the selective synthesis of two value-added chemicals by one tandem catalyst and deeply analyzes the adsorption enhancement mechanism of the catalyst, which provides a powerful guidance for the development of efficient heterogeneous catalysts.