Energy advances最新文献

Ag–NiP-deposited carbon channels on NiP panels were successfully developed through lemon juice extract (Ag–CL/NiP) and citric acid (Ag–CC/NiP)-assisted methodologies. The methods involved the precise execution of electroless deposition of the advanced Ag–carbon matrix with NiP. The lemon juice-assisted method produced carbon channels with a dense concentration of Ag–NiP on the electrode surface, whereas the citric acid method resulted in a less dense deposition of Ag–NiP on the electrode surface, as observed via FE-SEM. The Ag–CL/NiP has remarkably higher electro- and photocatalytic water splitting performance due to the compact and conductive Ag–NiP connected with carbon channels. Electrochemical impedance analysis of Ag–CL/NiP revealed a low R_ct of 491.3 Ω at the open circuit potential, indicating enhanced conductivity. The electrocatalytic oxygen evolution reaction (OER) overpotential of Ag–CL/NiP was 401 mV to achieve a current density of 50 mA cm⁻², with a Tafel slope of 46.5 mV dec⁻¹. The panel exhibited good stability, with a proven durability of over 1000 cycles of CV during OER. The developed panel achieved an impressive photocurrent density of ∼9.5 mA cm⁻² at 1.37 V vs. RHE when subjected to light irradiation with a wavelength exceeding 420 nm. Furthermore, the Ag–CL/NiP panel demonstrated the ability to generate 17.5 mmol cm⁻² of H₂ over a 4-hour sunlight irradiation period. The temperature-controlled photocatalytic water splitting experiment revealed that the panel maintained its activity at temperatures as low as ∼12 °C, but with a 40% drop in efficiency compared to normal sunlight conditions.

We show that a number of ubiquitous organic molecules used as redox mediators and chemically sensing species can be used as positive couples in electrochemical energy storage. Air and acid stable organic molecules were tested in aqueous acid electrolytes and employed as the positive electrolyte in H₂–organic electrochemical cells. The dissolved organic species were characterised in-operando using UV-vis spectroscopy. N,N,N′,N′-tetramethylbenzidine was found to be a stable and reversible redox organic molecule, with a 2 e⁻ molecule⁻¹ capacity and a 0.83 V cell potential. N-Oxyl species were also tested in purely aqueous acidic flow battery electrolytes. A H₂–violuric acid cell produced a reversible potential of 1.16 V and demonstrated promising redox flow cell cycling performance.

The redox flow battery is a cost-effective solution for grid-scale energy storage. Its special feature of separate reservoirs and electrodes makes it easy to adjust the electrolyte volume and electrode size, improving safety and scalability. In this work, we explore two organic anolytes, chelidamic acid (CDA) and chelidonic acid (CDO), which share similar molecular weight but differ in their heteroatoms: pyridone and pyrone. The half-cell potentials of the CDA and CDO anolytes enable them to exhibit theoretical cell voltages of 0.49 V and 0.48 V, respectively, when coupled with K₄[Fe^II(CN)₆] catholyte. CDA demonstrated a stable discharge capacity of 650 mA h L⁻¹ over 17 days in a basic medium without any degradation. In contrast, CDO gradually loses its capacity over successive cycles. The mechanism for the decomposition of CDO was analysed through cyclic voltammetry, ¹H-NMR, and FTIR spectroscopy techniques. The analytical results revealed that there was a significant impact of tautomerization in CDA and nucleophilic addition in CDO on the performance in ARFBs.

The coupling of multiple low-cost metals and porous nanocarbon materials aimed at replacing precious metals to enhance electrocatalytic oxygen reduction is a critical challenge in some crucial research areas. In the present study, a hollow dodecahedron nanocage catalyst (Fe₃O₄/CuNCs/ZnN_x-PHNC) was constructed by supporting copper nanoclusters, Fe₃O₄ nanoparticles, and Zn–N_x after sintering and annealing through the coordination of ZIF-8 and by doping copper and iron ions. We observed that the synergy of the multi-metals in the magnetically separable heterojunction catalyst induced electron transfer and inhibited hydrogen peroxide formation, thus improving its catalytic performance for the oxygen-reduction reaction. The catalyst demonstrated a half-wave potential as high as 0.832 V and a Tafel slope of 54 mV decade⁻¹, superior to many non-precious metal catalysts reported in the literature. The assembled Zn–air battery (ZAB) exhibited a maximum power density of 162 mW cm⁻² and ultrahigh stability of >500 h at 5 mA cm⁻² current density. The ZAB's excellent performance indicates its high development and practical application prospects.

BiOI is a promising material for use in photoelectrocatalytic water oxidation, renowned for its chemical inertness and safety in aqueous media. For device integration, BiOI must be fabricated into films. Considering future industrial applications, automated production is essential. However, current BiOI film production methods lack automation and efficiency. To address this, a continuous automated process is introduced in this study, named AutoDrop, for producing BiOI films. Autodrop results to be a fast and facile method for producing BiOI photoelectrodes. Nanostructured thin films of this layered material are prepared using a syringe pump to dispense the precursor solution onto a continuously spinning substrate. These films are integrated into a multilayered photoelectrode, featuring mesoporous TiO₂ as an electron-transporting layer on top of FTO glass. In testing the photoelectrochemical performance of the BiOI/TiO₂ photoelectrodes, the highest photocurrent (44 μA cm⁻²) is found for a heterojunction with a BiOI thickness of 320 nm. Additionally, a further protective TiO₂ ultrathin layer in contact with BiOI, grown by atomic layer deposition, enhances the durability and efficiency of the photoanode, resulting in a more than two-fold improvement in photocurrent after 2 hours of continuous operation. This study advances the automation in the sustainable production of photoelectrode films and provides inspiration for further developments in the field.

The lithium–sulfur battery (LSB) is a next generation energy storage technology with potential to replace lithium-ion batteries, due to their larger specific capacity, cheaper and safer manufacturing materials, and superior energy density. LSBs are a rapidly progressing topic globally, with around 1800 publications each year and the market is expected to exceed 1.7 billion USD by 2028, as such many novel strategies are being explored to develop and commercialise devices. However, significant technical challenges must be solved to engineer LSBs with commercially viable cycle life, which requires a deeper understanding of the chemical mechanisms occurring within the battery structure. In recent years in situ/operando testing of LSBs has become a popular approach for deciphering the kinetics and mechanisms of their discharge process, which is notoriously complex, and visualising the effects of mass deposition onto the electrodes and how these factors affect the cell's performance. In this review, in situ and operando studies are discussed in the context of LSBs with particular focus on spectroscopic and morphological techniques in line with trends in the literature. Additionally, some techniques have been covered which have yet to be used widely in the literature but could prove to be invaluable tools for analysis in the future. These in situ/operando techniques are becoming more widely available, and a review is useful both for the research community and industry to help accelerate the commercialisation of this next-generation technology.

Converting carbon dioxide (CO₂) into value-added chemicals is considered as a promising strategy to mitigate climate change. Among the various CO₂ reduction techniques, electrochemical CO₂ reduction (ECO₂R) using renewable energy sources holds significant potential. Consequently, the design and development of electrocatalysts capable of offering both high performance and cost-effectiveness hold the potential to expedite reaction kinetics and facilitate widespread industrial adoption. In recent years, abundant copper sulfide (Cu/S)-based nanomaterials among various metal–chalcogenides have attracted extensive research interest due to their semiconductivity and low toxicity, enabling them to be used in a wide range of applications in the ECO₂R field. This review highlights the progress in engineered Cu/S-based nanomaterials for ECO₂R reactions and elaborates on the correlations between engineering strategies, catalytic activity, and reaction pathways. This paper also summarises the controllable synthesis methods for fabricating various state-of-the-art Cu/S-based structures and outlines their possible implementation as electrocatalysts for CO₂ reduction. Finally, challenges and prospects are presented for the future development and practical applications of Cu/S-based catalysts for ECO₂R to value-added chemicals.

New-generation sustainable energy systems serve as major tools to mitigate the greenhouse gas emissions and effects of climate change. Biophotovoltaics (BPVs) presents an eco-friendly approach by employing solar energy to ensure self-sustainable bioelectricity. In contrast to other microbial fuel cells (MFCs), carbon feedstock is not essential for generating electricity with BPVs. However, the low power outputs (μW cm⁻²) obtained from the current systems limit their practical applications. In this study, a new generation polydimethylsiloxane (PDMS) based BPV cell unit was developed with a 3D hydrogel scaffold-based bio-anode to enable microbial biofilm formation for substantial electron capture and extracellular electron transfer. Moreover, the fabricated device was supported using an air-cathode electrode to elevate the gas exchange, thereby enabling optimum photosynthesis. Synechocystis sp. PCC 6803 seeded the 3D bio-anode embedded BPV cell, whose electrical characteristics were analyzed under the illumination of white light as day/night cycles with continuous feeding by the microchannel. For the first five days, the results indicated that the maximum power densities were 0.0534 W m⁻² for dark hours and 0.03911 W m⁻² for light hours without causing any effect on the cellular morphology of the cyanobacteria. As a result, the developed hydrogel scaffold-based bio-anode embedded BPV cell led to higher power densities via enabling a simple, self-sustainable, biocompatible, and eco-friendly energy harvesting platform with a possible capability in the applications of power lab-on-a-chip (LOC), point-of-care (POC), and small-scale portable electronic devices.

Energy scarcity and environmental issues can be effectively addressed via photocatalytic hydrogen production. The effective combination of semiconductor materials can prevent exciton recombination, making it a highly effective method for enhancing photocatalytic activity. This study details the synthesis of a conjugated polymer encapsulated with a metal oxide photocatalyst using a simple ex situ method. The encapsulation of the polymer with CeO₂ nanoparticles resulted in exceptional performance in H₂ production, exhibiting improved visible light absorption and a significant increase in charge transfer efficiency. This is attributed to the high charge transfer and reduced recombination in the composite. Moreover, photogenerated holes led to a substantial decline in the recombination rate of excitons and concomitant enhancement in the rate of photocatalytic H₂ production. Markedly, the observed hydrogen evolution for 10 wt% of CeO₂ doped C₃N₅ composites is 1256 μmol g⁻¹ h⁻¹, whereas for C₃N₅, it is 125 μmol g⁻¹ h⁻¹. Electrochemical analysis showed that the optimized composites exhibit a low electron–hole recombination rate, and UV-vis spectroscopic analysis showed improved visible light absorption resulting in excellent photocatalytic activity. Notably, the proposed system offers a novel strategy for hydrogen evolution via photocatalysis using CeO₂/C₃N₅ composites. Consequently, this research offers a new perspective on the design of organo–inorganic heterostructures and introduces a novel pathway to explore their catalytic capabilities.

The hybrid air-volt ammonia cracker (HAVAC) represents a novel approach to centralised ammonia cracking for hydrogen production, enhancing both efficiency and scalability. This novel process integrates renewable electricity and autothermal operation to crack blue or green ammonia, achieving a high thermal efficiency of 94% to 95%. HAVAC demonstrates impressive ammonia conversion rates up to 99.4% and hydrogen yields between 84% and 99.5%, with hydrogen purity of 99.99% meeting ISO 14687:2019 standards. Key innovations include the process's flexibility to operate in three modes: 100% renewable electricity, 100% air autothermal, or a hybrid approach. This versatility optimizes energy use and adapts to varying conditions. The gas heated cracker (GHC) within HAVAC efficiently reduces energy demands by utilizing waste heat. Modelled using the Aspen Plus Simulator and validated against experimental data, HAVAC's economic analysis indicates a levelized cost of hydrogen (LCOH) between $3.80 per kg-H₂ and $6.00 per kg-H₂. The process's environmental benefits include reduced greenhouse gas emissions and effective NOx waste management. Future research will focus on scaling up, reducing ammonia feed cost, optimizing catalysts, and enhancing waste management. HAVAC offers substantial promise for advancing hydrogen production and supporting a sustainable, carbon-free hydrogen economy. The technical and economic data generated by this analysis will assist decision-makers and researchers in advancing the pursuit of a carbon-free hydrogen economy.