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The electrocatalytic methanol conversion is of importance in direct methanol fuel cell, biomass reforming, and hydrogen generation. To achieve a “carbon-neutral” target, CO2 byproducts derived from biofuels should be mitigated. In contrast to the complete oxidation of methanol to CO2, the selective oxidation of methanol to formate is a CO2-emission-free route without the generation of toxic CO intermediates. Herein, we present a highly active catalyst based on transition-metal disulfide nanosheet arrays supported on Ni foam for methanol conversion. Through composition screening, we find that the FeCoNi disulfide nanosheet exhibits a highly efficient and selective methanol-to-formate conversion. The surface reconstruction of this catalyst allows us to produce 0.66 mmol cm−2 h−1 of formate at low potential (1.40 V) with high faradaic efficiency of > 98%. This work offers a substantial composition tuning strategy to construct noble-metal-free active multi-metal sites for CO2-emission-free conversion of methanol to value-added formate.

Electrochemical N2 reduction provides a green and sustainable alternative to the Haber-Bosch technology for NH3 synthesis. However, the extreme inertness of N2 molecules is a formidable challenge, which requires the development of an active electrocatalyst to drive the N2 reduction reaction (NRR) for NH3 production at ambient conditions. Herein, we demonstrate the development of La-doped TiO2 nanorods as an efficient NRR electrocatalyst for ambient NH3 synthesis. The optimized La-TiO2 catalyst offers a large NH3 yield of 23.06 μg h−1 mgcat−1 and a high Faradaic efficiency of 14.54% at –0.70 V versus reversible hydrogen electrode in 0.1 M LiClO4, outperforming most La- and Ti-based catalysts reported before. Significantly, it also demonstrates high electrochemical stability and its activity decay is negligible after 48 h test. The mechanism is further revealed by density functional theory calculations.

2,5-dimethyfuran (DMF), which is produced from 5-hydroxymethyfurfural (HMF) by hydrodeoxygenation (HDO), is a high quality fuel due to the high heating value, the high octane number and the suitable boiling point. Selective hydrogenation of HMF into liquid fuel DMF has been widely researched. In this paper, Co3O4 catalyst was prepared by co-precipitation and was reduced at different temperatures to form Co–CoOx catalysts. The characterization of catalysts was tested by XRD, TEM, XPS, TPR, BET and NH3-TPD. Co–CoOx possessed a high amount of Co metal and CoOx acidic sites, wherein Co worked as the active hydrogenation sites and CoOx acted as the acid promoter to facilitate the selective HDO of HMF to DMF. The synergistic effect of Co–CoOx is the key for HDO of HMF, obtaining 83.3% of DMF yield at 170 °C, 12 h and the reduction temperature of 400 °C. This method not only saves the catalyst cost, but also promotes the utilization of biomass energy.

By using the salting-out phenomenon to induce phase separation, the novel CO 2 phase change absorbents (CPCAs) composed of MEA/water-miscible alcohol/H 2 O were developed. The absorbents using 1-propanol, 2-propanol and tertiary butanol as the diluent were selected as CPCAs. The CPCAs composed of MEA/1-propanol/H 2 O were further examined include the species distributions in the two phases, physical properties, cyclic capacity and absorbent regenerability. In comparison to 30 wt% MEA/H 2 O, the optimal CO 2 cycle capacity of CPCA is 2.59 mol CO 2 /kg which increase 62% and the volume of CPCA sent to the stripper decreased over 67%. The developed CPCAs would benefit to reduce energy consumption of CO 2 capture.

Cocatalysts are usually deposited on semiconductors to accelerate charge transfer/separation and passivate their surface states. Although various methods have been developed to decorate cocatalysts on semiconductors, in situ depositing a transition metal oxide/oxyhydroxide catalyst in alkaline electrolyte remains a challenge. Herein, we present a facile in situ photo-assisted electrodeposition of ultrathin amorphous CoOxHy layer on hematite for efficient solar-driven water oxidation. Compared to Co(II) hydroxide, Co(III) hydroxide is much less soluble in alkaline electrolytes, thus being favorable for deposition above the anodic onset potential of Co(II)/(III). By using this metal valence dependent deposition-dissolution equilibrium, we prepared this highly efficient and adaptive CoOxHy layer on hematite for OER in 1.0 M NaOH containing 1.0 μM Co(II). This method is promising for loading cocatalysts on semiconductors for solar-driven water splitting and is general for developing in situ (photo)electrochemical deposition of nanoscale catalysts.

In modern technologies, the researchers are keen on top-down approaches to tailor the materials from bulk into their nanometer forms. For the amorphous alumina, this is the other way around. The amorphous alumina was receiving attention in the forms of thin films or nanoparticles many years ago, yet any attempts to increase the dimensions destabilized its amorphous structure and caused crystallization at even relatively modest temperatures. This issue has been addressed by smart engineering of its lattice strain, which allows the formation of a high-temperature stable bulk alumina. In this review, we present the recently developed synthetic methods and provide insights in sustaining the amorphous structure of widely used alumina. We highlight its adoptable short-range structure and morphology, emphasize the corresponding tuning of the mechanical and electronic properties, and illuminate the advanced applications in wear and scratch resistant coatings, corrosion protection, insulator layers, capacitor, luminescent material, and catalysis.

CaMoO4 thin films were prepared by an irreversible galvanic cell method at room temperature; the crystalline phase structure, surface morphology, chemical composition and room temperature photoluminescence property were characterized by X-ray diffraction, Raman spectroscopy, scanning electronic microscopy, X-ray photoelectron spectroscopy as well as photoluminescence spectroscopy. Our results reveal that it is very difficult to directly deposit dense and uniform CaMoO4 thin films in saturated Ca(OH)2 solution at room temperature by the irreversible galvanic cell method. After adding some oxidant (NaClO solution or H2O2 solution), the growth of CaMoO4 grains has been promoted, and well-crystallized, dense, and uniform CaMoO4 films were obtained. The as-prepared CaMoO4 films exhibit a good green photoluminescence, with the excitation of various wavelengths (220 nm, 230 nm, 240 nm, 250 nm and 270 nm) of ultraviolet irradiation.

The extraction ability of organophosphorus extractant D2EHPA (di-2-ethylhexyl phosphoric acid) and hydroximic extractant Lix984N are investigated by the extraction equilibrium experiments. Effects of carrier concentration and organic/aqueous volume ratio on the mass transfer of hollow fiber renewal liquid membrane (HFRLM) are studied. Results show that, in the extracting process, kerosene and n-heptane are more suitable than methyl-isobutyl ketone, butylacetate and benzene as the diluents of D2EHPA or Lix984N. The favorable feed pH is 4.4 for D2EHPA and 2.6 for Lix984N. The mass transfer flux of HFRLM increases with carrier concentration and finally reaches a plateau. The mass transfer flux and the overall transfer coefficient increase with the organic/aqueous volume ratio, reach the maximum and then decrease.

The transport of Cu(II) from aqueous solutions containing buffer media through hollow fiber supported liquid membrane (HFSLM) using di(2-ethylhexyl) phosphoric acid (D2EHPA) dissolved in kerosene as membrane phase and hydrochloric acid as striping phase was investigated. A set of factors were studied, including tube side velocity, shell side velocity, pH of the feed phase, Cu(II) concentration in the feed phase, buffer media concentration and D2EHPA concentration in the membrane phase. Experimental results indicate that the mass transfer coefficient increases with increasing both carrier concentration in the organic phase and flow rates on the tube side and shell side, and decreases with increasing initial Cu(II) concentration in the feed phase. With increasing pH value and acetate concentration in the feed phase, the mass transfer coefficient reaches a maximum value then decreases. The optimal operating conditions are obtained at pH value of 4.44 and 0.1 mol·L −1 acetic ion concentration in feed phase, and carrier volume fraction of around 10% in kerosene as organic phase. A mathematical model of the transport mechanism through HFSLM is developed. The modeled results agree well with the experimental ones.

Well-crystallized SrMoO 4 films have been prepared directly on molybdenum substrates in an alkaline aqueous solution containing strontium ions by a simple chemical reaction at room temperature. In order to keep the free growth of SrMoO 4 crystals in solutions, a mild oxidizing agent, NaClO, plays an important role in the formation of desired film. XRD and SEM results indicate that the films have single phase and uniform surfaces. The film shows a broad emission band centered at 487 nm with the excitation light of 240 nm, 250 nm and 270 nm at room temperature, respectively.

Highly crystallized luminescent SrWO 4 films were prepared directly on tungsten substrate in strontium hydroxide aqueous solution by a galvanic cell method without impressed current at room temperature. It is noteworthy that the driving force of galvanic cell method is adjustable by adding different concentrations of oxidant. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results reveal that the crystallized films have a scheelite-type tetragonal structure and homogeneous surface. The film showed single blue emissions at 447 nm with excitation lights of 220, 230, 250, 260 and 270 nm at room temperature, respectively.

Highly crystallized BaWO 4 films have been prepared by a galvanic cell method without impressed current on tungsten substrates at room temperature. The surface morphology, grain size and crystal phase of BaWO 4 films have been controlled effectively by adjusting ion-concentration, pH and even adding adequate surfactant. The BaWO 4 films are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD). The results indicate that the films have single phase and uniform surfaces. The grain size was changed under different treatment conditions.

BaMoO{sub 4} films have been prepared by a novel electrochemical technique without impressed current on molybdenum substrates at room temperature in barium hydroxide aqueous solution. In order to form desired surface morphology and grain size, the BaMoO{sub 4} crystal grains have been controlled effectively by adjusting ion-concentration and adding adequate surfactant. The as-prepared BaMoO{sub 4} films have been characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM and XRD results indicate that the morphology, grain size, phase and crystallinity were significantly developed.

Well-crystallized SrMoO4 thin films were synthesized directly on a molybdenum substrate by a non-reversible galvanic cell method through 150 h electrochemical reaction at room temperature. The as-synthesized thin films are a single phase SrMoO4 with a scheelite-type structure and show uniform and homogeneous surfaces. When excited by 290 nm ultraviolet ray at room temperature, the thin films emit the maximum peaks at 485 nm. The densification, chemical–physical and photoluminescence properties of the SrMoO4 thin films synthesized by the non-reversible galvanic cell method are significantly improved.

In this paper, a new liquid membrane technique, hollow fiber renewal liquid membrane (HFRLM), is presented, which is based on the surface renewal theory, and integrates the advantages of fiber membrane extraction, liquid film permeation and other liquid membrane processes. The results from the system of CuSO 4 + D 2 EHPA in kerosene + HCl show that the HFRLM process is very stable. The liquid membrane is renewed constantly during the process, the direct contact of organic droplets and aqueous phase provides large mass transfer area. These effects can significantly reduce the mass transfer resistance in the lumen side. Then the mixture of feed phase and organic phase flowing through the lumen side gives a higher mass transfer rate than that of stripping phase and organic phase, because the aqueous layer diffusion of feed phase is the rate-controlling step. The overall mass transfer coefficient increases with increasing flow rates and D2EHPA concentration in the organic phase, and with decreasing initial copper concentration in the feed phase. The overall mass transfer coefficient also increases with increasing pH in the feed phase, and reaches a maximum value at pH of 4.44, then decreases. Also, there is a favorable w / o volume ratio of 20:1 to 30:1 for this process. Compared with hollow fiber supported liquid membrane and hollow fiber membrane extraction processes, HFRLM process has a high mass transfer rate. Mathematical model for the HFRLM process based on the surface renewal theory is developed. The calculated results are in good agreement with experimental results under the conditions studied.

Highly crystallized luminescent CaMoO 4 film was prepared directly on molybdenum substrate in an alkaline aqueous solution containing calcium ions by a simple chemical reaction. To keep the free growth of CaMoO 4 crystals in solutions, an oxidizing agent (H 2 O 2 ) with lower concentration plays an important role in the formation of desired film. XRD and Raman results indicate that the film has single phase and SEM result shows uniform surfaces. The film shows a broad emission centered at 500 nm with the excitation light of 230 nm at room temperature. The formation mechanism of CaMoO 4 film under the simple chemical process has been discussed.

Highly crystallized CaWO 4 film has been prepared directly by a galvanic cell method on tungsten substrates in calcium hydroxide aqueous solution without impressed current at room temperature (25 °C). The scanning electron microscopy (SEM) and X-ray diffraction (XRD) results reveal that the crystallized film has a scheelite-type tetragonal structure, uniform and homogeneous surface. The film shows only the blue emission of 447.5 nm with the excitation light of 250 nm at room temperature. The formation mechanism of CaWO 4 film under the simple electrochemical process has been discussed. This method could resolve the repulsion of the electric field on the anode for the mass transfer. The crystal growth in the solution is freer.

Highly crystallized luminescent BaMoO 4 films have been prepared directly on molybdenum substrates at room temperature (25 °C) in barium hydroxide aqueous solution by a simple chemical reaction. In order to form the desired surface morphology and crystal structure, a mild oxidizing agent, NaClO, seems to be the key to the high crystallinity. In alkaline solution, the molybdenum substrate can gradually convert into MoO 4 2− ions, combined with Ba 2+ ions which have a poor migration just depending on thermal motion to form a film. XRD and SEM results indicate that the films have single phase and uniform surfaces. FA results reveal that the films appear to have scintillating luminescent character when they are under different excitations at room temperature. Further, the excitation and emission wavelengths comply with a linear relationship which will be a potential technological application of BaMoO 4 in a variety of optical devices.