NiFe (oxy)hydroxide (NiFeOOH) is recognized as a highly active non-precious metal catalyst in alkaline water electrolysis due to its exceptional catalytic properties. In this work, high valence molybdenum (Mo) is introduced to improve the electronic structure and enhance the electrical conductivity of NiFeOOH for oxygen evolution reaction (OER). The introduction of Mo results in a Mo-doped NiFeOOH catalyst with a significantly reduced overpotential of 205 mV at 10 mA/cm² and a Tafel slope of 31.7 mV/dec, enabling stable operation for up to 170 h. Both empirical experiment and theory simulations are employed to gain insight into the 3d-electron interactions between molybdenum and nickel (Ni), iron (Fe) in Mo-doped NiFeOOH. The results indicate that Mo-doping enhances the valence states of Ni and Fe, leading to a shift in the d-band center of the bimetallic active sites. This modification affects the transformation of Mo-doped NiFeOOH into the γ-NiFeOOH active phase. This potent combination lends credence to its potential suitability and utility in OER applications.

Ammonia is an exceptional fuel for solid oxide fuel cells (SOFCs), because of the high content of hydrogen and the advantages of carbon neutrality. However, the challenge lies in its unsatisfactory performance at intermediate temperatures (500‒600 °C), impeding its advancement. An electrolyte-supported proton-ceramic fuel cell (PCFC) was fabricated employing BaZr_0.1Ce_0.7Y_0.2O_3–δ (BZCY) as the electrolyte and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3–δ (BSCF) as the cathode. In this study, the performance of PCFC using NH₃ as fuel within an operating temperature range of 500‒700 °C was improved by adding an M(Ni,Ru)/CeO₂ catalyst layer to reconstruct the anode surface. The electrochemical performance of direct ammonia PCFC (DA-PCFC) were improved to different extents. Compared to H₂ as fuel, the degradation ratio of peak power densities (PPDs) of Ni/CeO₂-loaded PCFC fueled with NH₃ decreased at 700‒500 °C, with a decrease to 13.3% at 700 °C and 30.7% at 500 °C. The findings indicate that Ru-based catalysts have a greater promise for direct ammonia SOFCs (DA-SOFCs) at operating temperatures below 600 °C. However, the enhancement effect becomes less significant above 600 °C when compared to Ni-based catalysts.

In the park-level integrated energy system (PIES) trading market involving various heterogeneous energy sources, the traditional vertically integrated market trading structure struggles to reveal the interactions and collaborative relationships between energy stations and users, posing challenges to the economic and low-carbon operation of the system. To address this issue, a dual-layer optimization strategy for energy station-user, taking into account the demand response for electricity and thermal, is proposed in this paper. The upper layer, represented by energy stations, makes decisions on variables such as the electricity and heat prices sold to users, as well as the output plans of energy supply equipment and the operational status of battery energy storage. The lower layer, comprising users, determines their own electricity and heat demand through demand response. Subsequently, a combination of differential evolution and quadratic programming (DE-QP) is employed to solve the interactive strategies between energy stations and users. The simulation results indicate that, compared to the traditional vertically integrated structure, the strategy proposed in this paper increases the revenue of energy stations and the consumer surplus of users by 5.09% and 2.46%, respectively.

Fe-N-C catalysts are potential substitutes to displace electrocatalysts containing noble chemical elements in the oxygen reduction reaction (ORR). However, their application is hampered by unsatisfactory activity and stability issues. The structures and morphologies of Fe-N-C catalysts have been found to be crucial for the number of active sites and local bonding structures. In this work, dicyandiamide (DCDA) and polyaniline (PANI) are shown to act as dual nitrogen sources to tune the morphology and structure of the catalyst and facilitate the ORR process. The dual nitrogen sources not only increase the amount of nitrogen doping atoms in the electrocatalytic Fe-C-N material, but also maintain a high nitrogen-pyrrole/nitrogen-graphitic: (N-P)/(N-G) value, improving the distribution density of catalytic active sites in the material. With a high surface area and amount of N-doping, the Fe-N-C catalyst developed can achieve an improved half-wave potential of 0.886 V (vs. RHE) in alkaline medium, and a better stability and methanol resistance than commercial Pt/C catalyst.

The frame of membrane electrode assembly (MEA) influences the durability of proton exchange membrane fuel cell (PEMFC). In this paper, the thermal shock bench was applied as an accelerated aging test to explore the effect of frame sealing structure on MEA durability at different temperatures. Analysis of scanning electron microscope (SEM) images reveals that thermal shock results in the formation of cracks on the exposed proton exchange membrane (PEM) at the gap between the frame and the active area. Moreover, it breaks the bonding interface between the frame and the membrane and leads to the debonding of the adhesive, which exacerbates the risk of crossover of the reactant gas. A comparison of the single-layer and improved double-layer frame structures reveal that the mechanical damage is caused by frequent membrane wrinkles in the gap under temperature shock. However, addition of a cushion layer improves the continuity between the frame and the active area, and reduces deformation of the membrane, thereby preventing membrane damage.

Developing efficient anode catalysts for direct ammonia solid oxide fuel cells (NH₃-SOFCs) under intermediate-temperatures is of great importance, in support of hydrogen economy via ammonia utilization. In the present work, the pyrochlore-type La₂Zr_2–xNi_xO_7+δ (LZN_x, x = 0, 0.02, 0.05, 0.08, 0.10) oxides were synthesized as potential anode catalysts of NH₃-SOFCs due to the abundant Frankel defect that contributes to the good conductivity and oxygen ion mobility capacity. The effects of different content of Ni²⁺ doping on the crystal structure, surface morphology, thermal matching with YSZ (Yttria-stabilized zirconia), conductivity, and electrochemical performance of pyrochlore oxides were examined using different characterization techniques. The findings indicate that the LZN_x oxide behaves as an n-type semiconductor and exhibits an excellent high-temperature chemical compatibility and thermal matching with the YSZ electrolyte. Furthermore, LZN_0.05 exhibits the smallest conductive band potential and bandgap, making it have a higher power density as anode material for NH₃-SOFCs compared to other anodes. As a result, the maximum power density of the LZN_0.05-40YSZ composite anode reaches 100.86 mW/cm² at 800 °C, which is 1.8 times greater than that of NiO-based NH₃-SOFCs (56.75 mW/cm²) under identical flow rate and temperature conditions. The extended durability indicates that the NH₃-SOFCs utilizing the LZN_0.05-40YSZ composite anode exhibits a negligible voltage degradation following uninterrupted operation at 800 °C for 100 h.

Bio-oil from biomass pyrolysis cannot directly substitute traditional fuel due to compositional deficiencies. Catalytic hydrodeoxygenation (HDO) is the critical and efficient step to upgrade crude bio-oil to high-quality bio-jet fuel by lowering the oxygen content and increasing the heating value. However, the hydrocracking reaction tends to reduce the liquid yield and increase the gas yield, causing carbon loss and producing hydrocarbons with a short carbon-chain. To obtain high-yield bio-jet fuel, the elucidation of the conversion process of biomass catalytic HDO is important in providing guidance for metal catalyst design and optimization of reaction conditions. Considering the complexity of crude bio-oil, this review aimed to investigate the catalytic HDO pathways with model compounds that present typical bio-oil components. First, it provided a comprehensive summary of the impact of physical and electronic structures of both noble and non-noble metals that include monometallic and bimetallic supported catalysts on regulating the conversion pathways and resulting product selectivity. The subsequent first principle calculations further corroborated reaction pathways of model compounds in atom-level on different catalyst surfaces with the experiments above and illustrated the favored C–O/C=O scission orders thermodynamically and kinetically. Then, it discussed hydrogenation effects of different H-donors (such as hydrogen and methane) and catalysts deactivation for economical and industrial consideration. Based on the descriptions above and recent researches, it also elaborated on catalytic HDO of biomass and bio-oil with multi-functional catalysts. Finally, it presented the challenges and future prospective of biomass catalytic HDO.