A kind of oil-in-dispersion (OID) emulsion catalyst containing MoS2 nanoparticles has been developed for heavy oil aquathermolysis. The emulsion contained 10 wt% oil phase, and can maintain its stability over a broad pH range from 2 to 9 and a salinity of up to 500 mM, making it promising for field application. In the catalytic aquathermolysis of Shengli heavy oil at 200 °C for 24 h with a molybdenum loading amount of 100 μ g/g, a viscosity reduction of 73 % and an asphaltene content reduction of 39 % could be achieved. With the addition of 1 wt% tetralin as a hydrogen donor, the viscosity reduction ratio further increased to 92 %. Molecular dynamics simulation revealed that the emulsion catalyst promoted the distribution of asphaltenes at oil–water interface. After the addition of the emulsion, the solvent-accessible surface area of the oil droplet increased from 229 to 256 nm2, while the interfacial exposure of hydrophilic groups rose from 5.6 to 11.53 nm2, indicating a substantial expansion of the hydrophilic interfacial area with the addition of OID emulsion. To further elucidate the hydrogen-transfer pathway, anthracene was used as a probe and the GC–MS and 2H NMR analyses demonstrated that both water and tetralin acted as hydrogen donors during aquathermolysis and tetralin acting as the predominant hydrogen donor. While the emulsion induced the interfacial distribution of asphaltenes and enhanced catalyst–asphaltene contact at the interface, the hydrogen donor facilitated the saturation of polyaromatic structures in heavy oil. Both effects contributed to the significantly improved upgrading performance. Besides, the low-oil-phase emulsion catalyst benefits the efficient and cost-effective field applications.

Aquathermolysis is an effective technique for heavy oil exploitation. In this study, a series of transition metal formate (MF) catalysts with bifunction of hydrogen donating capacity and catalytic activity were synthesized. The viscosity reduction performance of catalysts has been studied with Shengli heavy oil at 250 degrees C. The property and molecular structures of oil samples and asphaltenes before and after catalytic aquathermolysis have been characterized. The results indicated that MFs could significantly improve the aquathermolysis reactions of heavy oil. Among these MF catalysts, cupric formate showed the highest activity, which could reduce the viscosity of the heavy oil by 74 % with the addition amount of only 0.5 wt%. At the optimal reaction condition, the relative content of asphaltenes and resin was decreased by 3.7 % and 15.6 % after aquathermolysis, respectively. And the sulfur content of asphaltenes was decreased by 20.98 %. Through the analysis of molecular structure changes of asphaltene and experimental results of model compounds, the catalytic mechanism and dual-function of MFs have been proved.

Catalyst deactivation caused by metal dissolution has constrained high-performance nickel-iron-based electrocatalyst development. This study innovatively repurposes metal dissolution as a structural design strategy. Crdoped NiFe-layered double hydroxide is synthesized, and a dual-activation strategy with descending alkali concentration enables relay Fe/Cr dissolution, constructing a dual anion-cation vacancy catalyst. During preactivation, Fe dissolves readily to form cation vacancies, whereas Cr, with its low-spin t2g3 configuration, stabilizes the framework via a more robust octahedral structure. During electro-activation, oxygen vacancies are formed while Cr relay dissolution creates cation vacancies. The dissolved Cr3+ oxidizes to CrO42 , which partly readsorbs on the surface. These vacancies and adsorbed anions synergistically tune active-site electronics, boosting OER performance. The resulting dR-NiFeCr-LDH catalyst requires overpotentials of only 235 and 284 mV to achieve current densities of 100 and 1000 mA cm 2, respectively. It also maintains stable operation for over 120 h under a high current density of 1 A cm 2 in a strongly corrosive 1 M KOH environment.

The active species CoOOH in Co-based catalysts, which drives the oxygen evolution reaction (OER), can be readily further oxidized to unstable CoO2at high potentials, resulting in poor catalytic stability. Interestingly, our work found that the reduction of unstable CoO2triggered by a decrease in potential during CV cathode scanning leads to a potential difference with CV anode scanning, resulting in a potential hysteresis effect. This effect indicates the generation of unstable CoO2. Herein, we report a strategy employing FeS as a dopant for the synthesis of Fe,S-co-doped Co(OH)2(denoted as CFSII). When FeS achieves equilibrium dissociation doping, it reduces the formation of S-M bonds, thereby constructing coordinated modulation of Fe,S co-doping. This not only regulates the electronic structure of Co to stabilize the active CoOOH by reducing the potential hysteresis effect, but also induces LOM mechanism. Consequently, the resulting catalyst demands an overpotential of only 267 mV to drive 10 mA cm-2, while maintaining stable operation for 100 h even at 1 A cm-2. This work analyzes the generation and reduction of high-valent states using the potential hysteresis effect as an indicator, providing a new direction for thermodynamic stability analysis of active materials.

Achieving highly efficient and stable oxygen evolution reaction (OER) electrocatalysts is fundamental for advancing hydrogen production via water splitting. Therefore, it is crucial to develop electrocatalysts containing the properties of superior activity, perfect stability, and low cost. We propose a simple one-step cyclic voltammetry-based electrodeposition strategy to synthesize Mo-doped NiFe LDH (NiFeMo LDH) with smaller nanoparticle clusters on a nickel foam. The optimal NiFeMo LDH requires an overpotential of 256 mV at a current density of 100 mA cm- 2, a Tafel slope of 42.4 mV dec- 1, and a Cdl value of 22.6 mF cm- 2 in 1 M KOH electrolyte, these parameters indicate that the electrocatalytic activity of NiFeMo LDH is considerably better than that of NiFe LDH. XPS, ICP-MS and other electrochemical tests indicate that the dissolution of Mo kept Ni and Fe species in low-valent states, and inhibited Fe leaching. This suggests that Mo doping effectively prevents the collapse of the layered structure caused by Fe dissolution. Concurrently, oxygen vacancies optimize enhance OHadsorption exhibiting strong activity. NiFeMo LDH-4 demonstrates high activity and remarkable stability, which was ascribed to Mo leaching electronic modulation and surface reconstruction which may provide a rational design strategy for advanced LDH-based OER catalysts.

The high activation temperature of catalysts and the difficulty of their dispersion in the formation are the main obstacles preventing the widespread application of catalytic hydrothermal cracking technology for heavy oil development. However, the "dual in-situ" strategy, which involves the in-situ generation of catalysts to achieve in-situ upgrading of heavy oil, holds promise as an ideal solution to overcome these challenges. Herein, a catalyst precursor suitable for the "dual in-situ" strategy was synthesized, and targeted decomposition experiments were conducted in both steam and oil-water environments typical of heavy oil thermal recovery. Additionally, oil displacement experiments in porous media were carried out, revealing the advantages and characteristics of this innovative oil displacement method in terms of heat transfer efficiency, oil displacement dynamics, and upgrading effects. The results showed that the final decomposition products of the synthesized cetyltrimethyl ammonium heptamolybdate in both steam and oil-water environments were catalytically active MoS2. In the oil water environment, due to solvent and interfacial effects, MoS3 could be converted to MoS2 at 180-200 degrees C, which was about 130 degrees C lower than in a nitrogen or steam atmosphere, fully meeting the conditions for integration with heavy oil thermal recovery. Furthermore, the presence of organic groups significantly enhanced the adsorption properties of the MoS2 generated from cetyltrimethyl ammonium heptamolybdate, with specific surface area and pore volume increasing by 110 m2/g and 0.04 cm3 /g, respectively. In the oil displacement experiments, the oil recovery after using cetyltrimethyl ammonium heptamolybdate increased by 10.3 % compared to steam flooding, and by 3.8 % compared to the direct injection of MoS2 NPs. The in-situ generation of the catalyst resulted in reduced agglomeration and deposition, leading to significantly improved mobility and sweep efficiency. Consequently, this approach not only enhanced the upgrading and production of heavy oil but also greatly extended the durability of the effect.

Heavy oil is an important unconventional petroleum resource due to its abundant reserve, but the reduction of viscosity is a prerequisite for its effective exploitation. Researchers are trying to develop heavy oil catalytic aquathermolysis technologies for their merit of irreversible viscosity reduction through in-situ upgrading. The key point of catalytic aquathermolysis is the in-situ formation of high active catalytic phase. In this study, we have demonstrated that the precursor (NH4)2MoS4 was fully decomposed into MoS2 nanoparticles at relatively low temperature of 200 degrees C after 90 minutes. The decomposition of (NH4)2MoS4 in aquathermolysis was significantly different from its decomposition process under hydrogen and vacuum atmospheres. The laboratory experimental results showed that the heavy oil viscosity reduction rate was above 85 % with the action of in- situ formed MoS2 nanoparticles after aquathermolysis. The sulfur content of heavy oil and asphaltene, asphaltenes and aromatics contents of heavy oil were decreased significantly, indicating that the cracking and ring opening reactions did take place. In the oilfield experiment, the precursor (NH4)2MoS4 was injected into the reservoir along with steam. After one-time injection, the catalytic effect could be sustained for at least four months. The maximum viscosity reduction rate was as high as 90 % during the first week, and still around 70 % in the 4th month. The molecular structural analysis of the produced heavy oil proved that the asphaltenes has been effectively cracked during the in-situ catalytic aquathermolysis. Both the laboratory and oilfield experimental results demonstrated that (NH4)2MoS4 precursor could form MoS2 nanoparticle and effectively catalyze the upgrading reactions of heavy oil. We hope that this study will provide a new catalyst development strategy for the catalytic aquathermolysis exploitation technology of heavy oil.

In order to address the issue of treating offshore drilling platform reinjection water, thin film composite (TFC) nanofiltration membranes exhibiting superior separation and hydrophilicity were fabricated by interfacial polymerization (IP) by piperazine and trimesoyl chloride and then coating Noria, finally a subsequent quick heating facilitates the formation of Noria-grafting polyamide (PA) layer. This approach introduces a large number of hydrophilic hydroxyl groups and a void-rich structure into the TFC membrane without inducing the intermolecular defects often caused by macrocyclic monomers. Additionally, the TFC membrane is made denser and more stable by the polyarylate framework created by the cross-linking reaction of Noria with unreacted trimesoyl chloride. Various characterisation tests including FTIR, SEM, AFM and XPS were carried out on the nanofiltration membranes and it was found that the increased hydrophilicity, effective penetration area and internal voids of Noria resulted in an increase in the pure water flux of the membranes, and the salt rejection of the nanofiltration membranes increased due to the increased surface charge density and reduced average pore size. The work has provided a promising strategy for designing efficient TFC membranes, breaking the “trade-off” between pure water flux and rejection of nanofiltration (NF) membranes.

In order to realize large-scale application of alkaline water electrolysis for hydrogen production, it is crucial to develop catalysts with cost-effective and balanced catalytic effects. Schottky heterojunction is considered as a potential material to realize efficient photoelectrocatalytic alkaline water electrolysis for hydrogen production, but its performance is limited by the built-in electric field (BIEF). Therefore, in this paper, we enhance the BIEF by doping trace amounts of Mn into Fe Urea/NF and optimize the energy band positions to reduce the forbidden bandwidths to obtain excellent photoelectrocatalytic performance. During oxygen evolution reaction (OER) only 270 mV overpotential was required to reach 100 mA cm-2 under light. Negligible overpotential changes were observed in the long-term stability test of close to 100 h under different conditions. The excellent performance of the catalysts was mainly attributed to the enhancement of BIEF, which implies that the incorporation of trace Mn accelerated the electron transport in the d-p-pi triple-orbital conjugated system and optimized the density of the electronic states in the active center, thus improving the oxidation state of the active iron. In addition, the incorporation of trace Mn effectively improves the positions of the valence and conduction bands, which in turn reduces the forbidden band width and improves the light absorption capacity. The choice of valence element Mn doping in this work provides a strong reference for designing strong BIEF heterojunction catalysts for efficient OER.

The low retention efficiency of catalysts in reservoirs limits the sustained effectiveness of heavy oil catalytic upgrading. This characteristic is closely related to the catalyst's adsorption behavior in the reservoir. Herein, A MoS2-based catalytic precursor (cetyltrimethyl ammonium heptamolybdate) was synthesized. Innovatively, static and dynamic adsorption experiments were designed to systematically investigate the adsorption mechanism in porous reservoir media through adsorption kinetics and thermodynamic analyses. The effects of temperature, permeability, flow rate, and precursor injection volume on dynamic adsorption were also evaluated, and a multi-factor control equation was developed to describe the adsorption process. The results showed that the enthalpy change, entropy change, and average free energy of the adsorption process of precursor in the lipophilic quartz sand-liquid system were -20.320 kJmol(-1), -0.028 kJ/(molK), and 11.17 kJmol(-1), respectively. Compared to similar water-soluble precursor (ammonium tetrathiomolybdate), cetyltrimethyl ammonium heptamolybdate exhibited stronger adsorption capacity and thermodynamic stability, with adsorption mainly occurring in the form of a bilayer or multilayer. At a concentration of 600 mgL-1, cetyltrimethyl ammonium heptamolybdate achieved an adsorption efficiency of 54.5 %, which was 24.2 % higher than that of ammonium tetrathiomolybdate. The dynamic adsorption capacity of cetyltrimethyl ammonium heptamolybdate decreased with increasing temperature and permeability, while it increased with increasing injection volume and flow rate. The priority order of the influencing factors was: precursor injection volume > temperature > permeability > flow rate. These insights provided critical guidance for optimizing catalyst deployment strategies and advancing sustainable EOR technologies.

The complex system of high-entropy materials makes it challenging to reveal the specific function of each site for oxygen evolution reaction (OER). Here, with nickel foam (NF) as the substrate, FeCoNiCrMo/NF is designed to be prepared by metal–organic frameworks (MOF) as a precursor under an argon atmosphere. XRD analysis confirms that it retains a partial MOF crystal structure (characteristic peak at 2θ = 11.8°) with amorphous carbon (peaks at 22° and 48°). SEM-EDS mapping and XPS demonstrate uniform distribution of Fe, Co, Ni, Cr, and Mo with a molar ratio of 27:24:30:11:9. Electrochemical test results show that FeCoNiCrMo/NF has excellent OER characteristics compared with other reference prepared samples. FeCoNiCrMo/NF has an overpotential of 285 mV at 100 mA cm−2 and performs continuously for 100 h without significant decline. The OER mechanism of FeCoNiCrMo/NF further reveal that Co and Ni are true active sites, and the dissolution of Cr and Mo promote the conversion of active sites into MOOH following the lattice oxygen mechanism (LOM). The precipitation–dissolution equilibrium of Fe also plays an important role in the OER process. The study of different reaction sites in complex systems points the way to designing efficient and robust catalysts.

II -conjugated organic compounds (n-COCs), as a potential electrode material, mainly emphasized the effects of functional groups and intramolecular n -conjugated system on charge storage in the past studies. In this work, we discovered a brand-new two step energy storage mechanism for n-COCs using oligomeric naphthalene (ONA) with intermolecular n -n stacking structure as electrode material in Al ion battery system. The electrochemical reaction of ONA is identified as the synergistic work of the chemical -adsorption of AlCl4- anions at low potential and the n center dot center dot center dot[AlCl4]center dot center dot center dot n interaction at high potential. Based on this, the Al-ONA battery exhibits an excellent electrochemical performance (high specific capacity of 450 mAh/g at 0.1 A/g, long cycle life without attenuation for 4000 cycles at 1 A/g). This discovery of the energy storage mechanism, especially for the n center dot center dot center dot anion center dot center dot center dot n interaction, for n-COCs materials opens the door to exploring high performance organic electrode materials in energy storage field.

The proton exchange membrane (PEM) water hydrolyzer is crucial to promoting the sustainable development of hydrogen energy and facilitating large-scale energy transformation. However, achieving sustained and stable oxygen evolution reaction (OER) in acidic solutions presents a significant challenge for noniridium based electrocatalysts. Herein, we develop a Co3O4-supported RuO2 electrocatalyst with optimized catalyst-support interface interactions for breaking the activity-stability trade-off relationship in acidic OER. Through detailed electrochemical experiments and characterization analysis, we demonstrate that the crystal growth of Co3O4 support can be precisely regulated by modifying the ligand layer-confined domain of cobalt-based metal-organic frameworks (Co-MOF) precursor, thereby optimizing the RuO2/Co3O4 interface. Due to the weakened self-sacrifice effect of Co3O4, active heterogeneous interface electron interaction and impeccable support crystal coating effect, the acidic OER stability of RuO2/Co3O4-B3DC is significantly improved compared with RuO2 while preserving intrinsic activity. Theoretical modeling suggests that the formation of a RuO2/Co3O4 catalyst-support interface optimizes the adsorption energy of oxygen intermediates, promoting the oxygen evolution process. Additionally, the RuO2/Co3O4-B3DC anode demonstrates promising potential application in PEM electrolyzers and a variety of renewable energy-driven electrolytic cells.

The Co-free Ni-rich layered cathode materials with excellent structural stability and low-cost in Ni-rich family are emerging as the promising candidates for the next generation of high-energy density cathodes. Previously, Mn is generally regarded as the structural stabilizer in Co-free Ni-rich cathodes, while the role of inevitable Li/Ni intermixing is underestimated. Herein, the study reveals that the real origin of the lattice oxygen/structure stability of Co-free Ni-rich cathodes is dominated more by Li/Ni intermixing than the widely accepted Mn. In the Li/Ni intermixing configuration, the intermixed Ni ions can suppress the oxidation of lattice oxygen by increasing the formation energy of oxygen vacancy and reducing charge compensation. Besides, the Li vacancy formed via the delithiation of intermixed Li in transition metal layer can serve as O2 capture sites. This dual stabilization mechanism is proposed and proved to be effectively in enhancing the reversibility of lattice oxygen and the stability of material structural. This work sheds light on the mechanism of stabilizing lattice oxygen through Li/Ni intermixing, which provides new insights for designing better batteries. The dual oxygen stabilization mechanisms of Ni and Li ions in Li/Ni intermixing configurations for inhibiting oxygen vacancy formation and storing O2 are proposed, which reveal that the real origin of the lattice oxygen and structure stability in Co-free Ni-rich cathode materials is Li/Ni intermixing rather than the traditional Mn stabilization mechanism.image

The use of transition metal phosphides for hydrogen evolution reaction has been continuously reported in recent years, but their excessive H* adsorption is detrimental to H2 desorption, as well as their limited specific surface area restricts the exposure of their active sites. Herein, we synthesized CoP by a molten salt method and gas phosphorylation and obtained the target catalyst B-CoP by further treating it with NaBH4 solution. Under the action of NaBH4, a large number of oxide impurities on the surface of the catalyst precursor reacted, generating a large number of oxygen vacancies and partially transforming the CoP of the crystalline-phase structure into an amorphous phase, which resulted in a large number of pore structures and a substantial increase in the specific surface area of the generated B-CoP catalyst. The special nanostructure allows the catalyst to increase the contact area with the electrolyte and accelerates the desorption of gas bubbles, which results in the catalyst exhibiting such a superior catalytic activity, with overpotentials of 104, 156, and 188 mV at 100, 500, and 1000 mA cm-2 current densities, respectively, and can be operated stably at 100 mA cm-2 current density for 100 hours. This work provides new ideas for efficient catalysts for hydrogen evolution reaction from phosphides.

Porous alumina with high specific surface area (SSA) and large pore volume (PV) is highly desired in various applications; however, its synthesis without an organic template faces a great challenge. Herein, we propose a novel template-free strategy based on intercalation-exfoliation with silica to weaken boehmite (alumina precursor) interlayer forces and achieve the exfoliation of boehmite into two-dimensional (2D) nanosheets, which can easily be scaled up. The as-prepared 2D nanosheets with 2-nm thickness could be assembled to form boehmite with 542 m 2 g −1 SSA and 2.43 cm 3 g −1 PV. The porous alumina obtained from the thermal/hydrothermal treatment of the 2D nanosheets at different temperatures possesses a hierarchical porous structure superior to most of the reported alumina synthesized with organic templates, exhibiting excellent performance in the adsorption of large organic molecules. This research provides a new strategy for synthesizing 2D boehmite nanosheets and porous alumina materials, demonstrating great potential in catalysis and adsorption.

It has been extensively researched that oxygen evolution reaction (OER) in alkaline conditions involves dynamic surface restructuring. In particular, the development and design of sulfide/oxide pre-catalyst can reasonably adjust the composition and structure after surface reconstruction, which is very important for oxygen evolution reaction. Herein, a simple two-step hydrothermal method was used to achieve in situ S leaching and doping by precipitation-dissolution equilibrium, inducing the composition change and structure reconstruction of CoFe oxides. In addition, the cross-linked nanosheet structure generated in situ widely exposes the active area, and the crystal/amorphous interface accelerates the charge and mass transfer efficiency. The structurally transformed FeOOH and CoOOH showed excellent OER activity, with overpotentials of 299 and 322.2 mV at 50 and 100 mA cm-2, significantly superior to one-step or uncured catalysts. Low-cost iron based materials combined with simple methods can be easily mass-produced. This provides an opportunity for the effective design of heterogeneous surface reconfigurable electrocatalysts for practical water electrolysis.

Sludge anaerobic digestion promoted by enzymes has the advantages of mild reaction,high efficiency and environmental protection etc.However,the difficulty of recovery and poor catalytic stability seriously restrict its ap-plication.Enzyme immobilization is the key to solve the above problems.A new type of polyvinyl alcohol(PVA)car-rier was prepared by Noria and polyethylenimide(PEI)co-deposition.The effect of lysozyme immobilized with Noria-PEI modified PVA carriers on the efficiency of sludge anaerobic fermentation for VFAs production was studied.The results showed that immobilized lysozyme could enhance sludge fermentation to promote SCOD,and SCOD reached the highest concentration of 2 892.4 mg/L within 36 h,which was 3.4 times higher than in the blank(day 6).VFAs concentration peaked at 2 130.8 mg/L on day 4,mainly comprised of acetic acid and propionic acid,accounting for 61.8%-80.7%.The average particle size and specific surface area of sludge in the immobilized enzyme system were 42.957 µm and 0.413 m2/g,indicating that immobilized enzyme enhanced the hydrolysis of granular sludge.Micro-bial community analysis showed that the hydrolytic acid-producing phyla of Firmicutes,Proteobacteria and Bacteroi-des accounted for high proportion in the immobilized enzyme system.At the genus level,Macellibacteroides,Petri-mona,Lactobacillu,and Clostridium_sensu_stricto_1 were the main genera,which revealed the mechanism of en-hanced VFAs production by the immobilized enzyme at microscopic level.

The poor conductivities and instabilities of accessible nickel oxyhydroxides hinder their use as oxygen evolution reaction (OER) electrocatalysts. Herein, we constructed Fe-NiOOH-OV-600, an Fe-doped nickel oxide hydroxide with abundant oxygen vacancies supported on nickel foam (NF), using a hydrothermal method and an electrochemical activation strategy involving 600 cycles of cyclic voltammetry, assisted by the precipitation/dissolution equilibrium of ferrous sulfide (FeS) in the electrolyte. This two-step method endows the catalyst with abundant Fe-containing active sites while maintaining the ordered structure of nickel oxide hydroxide (NiOOH). Characterization and density functional theory (DFT) calculations revealed that synergy between trace amounts of the Fe dopant and the oxygen vacancies not only promotes the generation of reconstructed active layers but also optimizes the electronic structure and adsorption capacity of the active sites. Consequently, the as-prepared Fe-NiOOH-OV-600 delivered large current densities of 100 and 1000 mA cm-2 for the OER at overpotentials of only 253 and 333 mV in 1 mol/L KOH. Moreover, the catalyst is stable for at least 100 h at 500 mA cm-2. This work provides insight into the design of efficient transition-metal-based electrocatalysts for the OER.

In situ combustion of heavy oil is currently the most suitable thermal method that meets energy consumption and carbon dioxide emission requirements for heavy oil recovery. The combustion catalyst needs to perform multiple roles for application; it should be capable of catalyzing heavy oil combustion at high temperatures, as well as be able to migrate in the geological formation for injection. In this work, a hyperbranched polymer composite nanometal fluid was used as the injection vector for a heavy oil in situ combustion catalyst, which enabled the catalyst to rapidly migrate to the surface of the oil phase in porous media and promoted heavy oil cracking deposition at high temperatures. Platinum (Pt) nanoparticles encapsulated with cetyl-hyperbranched poly(amide-amine) (CPAMAM), with high interfacial activity, were synthesized by a facile phase-transfer method; the resulting material is called Pt@CPAMAM. Pt@CPAMAM has good dispersion, and as an aqueous solution, it can reduce the interfacial tension between heavy oil and water. As a catalyst, it can improve the conversion rate during the pyrolysis of heavy oil in a nitrogen atmosphere. The catalyst structure designed in this study is closer to that exhibited in practical geological formation applications, making it a potential method for preparing catalysts for use in heavy oil in situ combustion to resolve the problem of catalyst migration in the geological formation.