The challenges posed by climate change and greenhouse gas net-zero transition are discussed. Several key technology areas which require innovation are briefly reviewed in this article, including renewables, energy storage, distributed energy resources, CO2 utilization, agriculture, and the synergy between Al and energy transition. The shift in mindset from “re-cycling” to “re-using” and a redefinition of “wealth” for a more sustainable future are also proposed.
Bioluminescent plankton are marine organisms capable of emitting visible light through chemical reactions in their bodies. This unique biochemical trait is attributed to a luciferin-luciferase reaction, which produces a striking blue light. This fascinating phenomenon, often referred to as the “blue tears” effect, has become a major attraction for tourist attractions in many countries. Since their discovery, most investigations related to these marine organisms have primarily focused on the fields of biology, ecology, oceanography, and microbiology. However, there has been limited to almost no study of their potential applications in the area of energy or lighting. This paper provides viewpoints on the opportunities for using these marine organisms and their light-emitting characteristics as an energy-efficient and environmentally friendly lighting solution, rather than just as a tourist attraction. Additionally, it addresses the challenges associated with sustaining the growth of bioluminescent plankton collected from the marine environment, the importance of establishing suitable protocols for in-house cultivation, challenges in stimulating the light-production at desired time, constraint imposed by the circadian rhythm, the toxicity of certain bioluminescent plankton, and the capacity of their luminous intensity.
Mesoporous biochar (MC) derived from biomass is synthesized using a dual-salt template method involving ZnCl2 and KCl, followed by impregnation with polyethyleneimine (PEI) of varying average molecular weights under vacuum conditions to construct a core-membrane structure for enhancing carbon capture performance. The resulting MC exhibits a highly intricate network of micropores and abundant mesopores, along with defects in graphitic structures, effectively facilitating robust PEI loading. Among the PEI-modified samples, PEI-600@MC demonstrates the highest CO2 sorption capacity, achieving approximately 3.35 mmol/g at 0.1 MPa and 70 °C, with an amine efficiency of 0.32 mmol CO2/mmol N. The introduction of amine functional groups in PEI significantly enhances the sorption capacity compared to bare MC. Additionally, PEI with lower average molecular weights exhibits a superior sorption performance at low pressures but shows a reduced thermal stability compared to higher molecular weight counterparts. The area of sorption hysteresis loops gradually decreases with increasing temperature and average molecular weight of PEI. The equilibrium sorption isotherms are accurately modeled by the Langmuir equation, revealing a maximum sorption capacity of approximately 3.53 mmol/g at 70 °C and saturation pressure. This work highlights the potential of dual-salts templated biomass-derived MC, modified with PEI, as an effective, widely available, and cost-efficient material for CO2 capture.
As the installed capacity of renewable energy such as wind and solar power continues to increase, energy storage technology is becoming increasingly crucial. It could effectively balance power demand and supply, enhance allocation flexibility, and improve power quality. Among various energy storage technologies, liquid CO2 energy storage (LCES) stands out as one of the most promising options due to its advantages such as high round-trip efficiency (RTE), high energy storage density (ESD), safety, stability, and longevity. Within the system, the cold and heat storage units play a critical role in determining the overall performance of the system and are particularly important among its various components. In this paper, a novel LCES system is proposed and the heat transfer characteristics are analyzed in detail. Then, the impact of key parameters on the liquefaction ratio and RTE is discussed. The results indicate that the RTE, ESD, and exergy efficiency of the system are 56.12%, 29.46 kWh/m3, and 93.73% under specified design conditions, respectively. During the gas–liquid phase change process of carbon dioxide or when it is in a supercritical state, the related heat transfer processes become more complex, leading to increased energy loss. The analysis of key parameters of the Linde-Hampson liquefaction unit reveals that as the liquefaction temperature decreases, both the liquefaction ratio and RTE increase. While the liquefaction pressure has a minimal impact on the liquefaction ratio, it significantly affects RTE, with an optimal liquefaction pressure identified.
Two-dimensional (2D) materials have emerged as a significant class of materials promising for photocatalysis, and defect engineering offers an effective route for enhancing their photocatalytic performance. In this mini-review, a first-principles design perspective on defect engineering in 2D materials for photocatalysis is provided. Various types of defects in 2D materials, spanning point, line, and planar defects are explored, and their influence on the intrinsic properties and photocatalytic efficacy of these materials is highlighted. Additionally, the use of theoretical descriptors to characterize the stability, electronic, optical, and catalytic properties of 2D defective systems is summarized. Central to the discussion is the understanding of electronic structure, optical properties, and reaction mechanisms to inform the rational design of photocatalysts based on 2D materials for enhanced photocatalytic performance. This mini-review aims to provide insights into the computational design of 2D defect systems tailored for efficient photocatalytic applications.
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 BaZr0.1Ce0.7Y0.2O3–δ (BZCY) as the electrolyte and Ba0.5Sr0.5Co0.8Fe0.2O3–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.