Energy advances最新文献

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.

Hydrogen generation through a photocatalytic process appears to be a promising technology to produce this energy vector through a novel, efficient, green, and sustainable process. The fruitful use of sunlight as an excitation source and renewable bio-derived reactants as well as the development of highly efficient catalysts are required to achieve this goal. In this perspective article, we focus on describing how to braid energy and sustainability sides of hydrogen photo-generation into a single parameter, allowing quantitative measurement and trustful comparison of different catalytic systems. Starting from the energy-related efficiency parameters defined by the IUPAC, we present novel approaches leading to parameters enclosing energy and sustainability information. The study is completed with the analysis of other, non-IUPAC, parameters of broad use such as the solar-to-hydrogen observable. The set of results available in the literature for the water splitting reaction and the use of bio-derived sacrificial molecules are reviewed to assess the potential of such reactions in the energy-efficient and sustainable production of hydrogen.

Correction for ‘Acid–base concentration swing for direct air capture of carbon dioxide’ by Anatoly Rinberg and Michael J. Aziz, Energy Adv., 2024, https://doi.org/10.1039/d4ya00251b.

The oxygen evolution reaction (OER) is usually the bottleneck in water electrolysis due to its sluggish kinetics, resulting in increased costs in the production of green hydrogen. Therefore, there is a need for more efficient, stable, and ideally, critical-raw-material-free catalysts. To this end, we have synthesized nanosized spinel ferrites CoFe₂O₄, NiFe₂O₄, and ZnFe₂O₄, and a high-entropy spinel ferrite Zn_0.2Mn_0.2Ni_0.2Co_0.2Fe_2.2O₄ through a simple coprecipitation reaction in an automated reactor on a gram scale. The powder X-ray diffraction and transmission electron microscopy studies revealed crystallite sizes of 20–35 nm. Insight into the oxidation states and cation distribution in the mixed spinel systems was gained through X-ray photoelectron and Mössbauer spectroscopy studies. The activity of all spinel ferrites was tested for the OER through half-cell laboratory measurements and full-cell anion exchange membrane electrolysis (AEMEL), where Zn_0.2Mn_0.2Ni_0.2Co_0.2Fe_2.2O₄ showed the lowest overpotential of 432 mV at a current density of 10 mA cm⁻². All the synthesized ferrites demonstrated good stability up to 20 h, with NiFe₂O₄ being the most active in high current density experiments up to 2 A cm⁻². In addition, studies on the magnetic properties at room temperature revealed a largely superparamagnetic response of the prepared materials, indicating that quantum spin-exchange interactions facilitate oxygen electrochemistry. Computational calculations shed light on the superior catalytic activities of NiFe₂O₄ and Zn_0.2Mn_0.2Ni_0.2Co_0.2Fe_2.2O₄, the two strongly correlated oxides that exhibit the highest magnetization and the smallest band gaps, corroborating the recent principles determining the activity of magnetic oxides in electron transfer reactions.

Fuels can be produced from the electrochemical reduction of industrial waste CO₂ (e-fuels) using renewable energy and hence are an attractive option for the storage of renewable energy in a chemical form. The energy stored in the e-Fuel may be recovered on-demand using a direct fuel cell thus completing a carbon neutral cycle. Anion exchange membrane fuel cells (AEMFCs) are versatile devices that can be fed by both a gaseous fuel such as H₂ and with liquid fuels (e.g. alcohols, formate, hydrazine, NaBH₄). Formate is a molecule that can be easily obtained by the electrochemical reduction of CO₂ with high selectivity. Efficient re-transformation of the energy stored in the chemical bonds into electrical energy requires the development of efficient and stable electrocatalysts. Palladium alloy catalysts are highly active under alkaline conditions when Pd is mixed with more oxophilic transition metals. Here we report that enhanced activity and stability can be obtained with Au–Pd alloy nanoparticles when compared to a Pd catalyst. Both catalysts are prepared by a metal vapour synthesis method. We show that the key to enhanced performance is the partial segregation of Au to the NP surface that increases oxophilicity and favours the adsorption and transfer of OH⁻ species to the active Pd sites. This enhanced activity translates to high power densities and performance stability when employed in AEMFCs fed with aqueous potassium formate fuel (Peak power density of 0.14 W cm⁻², energy efficiency of 33%, faradaic efficiency of 80%).