Lisandra Rocha-Meneses

Metal oxide nanomaterials are among the most compelling electrode materials for supercapacitors. In contrast to carbon‐based electrodes that store charge via electric double‐layer mechanisms, pseudocapacitive materials operate through rapid, reversible surface or near‐surface redox reactions, enabling higher densities. This review examines the non‐aqueous solvothermal synthesis of nine major transition metal oxide nanomaterials (Fe ₃ O ₄ , Co ₃ O ₄ , NiO, RuO ₂ , V ₂ O ₅ , CuO, WO ₃ , Nb ₂ O ₅ , and MnO ₂ ). Solvothermal synthesis is a powerful and indispensable strategy for tailoring the intrinsic physicochemical properties of these nanomaterials, that is, phase composition, crystallinity, morphology, and particle size, that directly govern their pseudocapacitive performance. We focus on a critical gap in literature: the limited reporting and understanding of key solvothermal parameters, particularly solvent identity and reactor fill ratio. These variables dictate autogenous pressure and determine whether the synthesis occurs under subcritical or supercritical conditions. Therefore, we propose a conceptual framework linking solvent choice and fill ratio to autogenous pressure, phase evolution, defect chemistry, morphology, and pseudocapacitive behavior. Because systematic studies remain scarce, existing evidence is critically evaluated to identify trends and knowledge gaps. The findings suggest that optimizing pristine metal oxide nanostructures through controlled solvothermal synthesis, rather than relying on conductive‐carbon compositing, is essential for achieving meaningful improvements in next‐generation supercapacitors.

The agricultural and livestock sectors of Latin America produce a large number of residues that could be converted into energy through bioenergy production processes. However, the bioenergy sector still faces several limitations across the region, including fragmented logistics systems, weak coordination among institutions, and limited integration of environmental, digital, and compliance-related performance indicators. This review systematically analyses residue-based bioenergy value chains in Latin America between 2015 and 2025 using the PRISMA methodology to evaluate selected peer-reviewed studies and regional reports indexed in Scopus, ScienceDirect, SpringerLink, and IEEE Xplore, and institutional repositories. The final synthesis included 37 studies and institutional contributions, which were further disaggregated into 208 country–residue observations for the regional and feedstock distribution analysis. The review identified three main research gap categories: the limited integration of collection and logistics systems, the insufficient treatment of uncertainty, circularity, and traceability within optimization models, and the weak incorporation of governance and institutional coordination into bioenergy value-chain design. The analysis includes biogas, biomethane and related residue-based systems, with attention to supply-chain optimization, policy alignment, methane mitigation metrics, and traceability requirements. Results indicate that although technologies such as biomass pretreatment, process intensification, and upgrading processes continue to improve conversion performance, most studies still focus mainly on technical feasibility and biomass potential. Less attention is given to governance constraints, uncertainty analysis, and monitoring systems capable of supporting regulatory compliance. This research introduced the Sustainable Bioenergy Chain Management Framework (SBCMF) to respond to these limitations and bring together different aspects of bioenergy management within one analytical structure. The framework combines supply-chain optimization under spatial and temporal constraints, circular economy valorisation, methane-related climate performance, and digital traceability, while also linking techno-economic system design with governance and monitoring requirements. In this way, it can help support the development of more transparent and low-carbon bioenergy systems across Latin America.

The transition to sustainable energy sources has intensified interest in lignocellulosic biomass (LCB) as a feedstock for second-generation biofuels. However, the inherent structural recalcitrance of LCB requires the utilization of an effective pretreatment to enhance enzymatic hydrolysis and subsequent fermentation yields. This manuscript presents a novel, single-step, and optimized nitrogen explosive decompression system (NED 3.0) designed to address the critical limitations of earlier NED versions by enabling the in situ removal of inhibitory compounds from biomass slurry and fermentation inefficiency at elevated temperatures, thereby reducing or eliminating the need for post-treatment detoxification. Aspen wood (Populus tremula) was pretreated by NED 3.0 at 200 °C, followed by enzymatic hydrolysis and fermentation. The analytical results confirmed substantial reductions in common fermentation inhibitors, such as acetic acid (up to 2.18 g/100 g dry biomass) and furfural (0.18 g/100 g dry biomass), during early filtrate recovery. Hydrolysate analysis revealed a glucose yield of 26.41 g/100 g dry biomass, corresponding to a hydrolysis efficiency of 41.3%. Fermentation yielded up to 8.05 g ethanol/100 g dry biomass and achieved a fermentation efficiency of 59.8%. Inhibitor concentrations in both hydrolysate and fermentation broth remained within tolerable limits, allowing for effective glucose release and sustained fermentation performance. Compared with earlier NED configurations, the optimized system improved sugar recovery and ethanol production. These findings confirm the operational advantages of NED 3.0, including reduced inhibitory stress, simplified process integration, and chemical-free operation, underscoring its potential for scalability in line with the EU Green Deal for bioethanol production from woody biomass.

Co-pyrolysis has become an eye-catching process for obtaining fuel and biochar and is attracting attention from both the scientific and industrial communities. One of the reasons for this is the wide variety of raw materials for the process itself and the possibility of obtaining attractive and high-quality products. The influence of three distinctive parameters has been studied on the co-pyrolysis reaction. These variables were temperature, reaction time, and plastic ratio. The results were analysed using Response Surface Methodology (RSM), and it was found that the optimum conditions to produce biochar from the co-pyrolysis of coffee and tire wastes were 359.441 °C, 10 minutes of reaction duration, and a plastic ratio of 97.8528 wt.%.

Open access peer-reviewed chapter