This experimental and modeling study explores the integration of renewable energy-based pretreatment methods (solar thermal and ultrasonic) with anaerobic digestion (AD) for sustainable sludge management and enhanced biogas production. Building on prior experimental work that utilized microwave pretreatment, the study employs machine learning (ML) to model and optimize AD performance under renewable energy pretreatment. Experimental validation was conducted using lab-scale continuously stirred tank reactors (CSTRs) with a comprehensive dataset of experimental runs. Key findings demonstrate that solar thermal and ultrasonic methods achieve 20.5% ± 1.8% and 18.7% ± 2.1% higher methane production (295 ± 22 and 285 ± 20 mL CH₄/g VS, respectively) and 30.9% ± 2.1% greater chemical oxygen demand (COD) solubilization compared to microwave pretreatment (245 ± 18 mL CH₄/g VS), while reducing energy consumption by 40.1% ± 3.2% and 35.6% ± 2.8%, respectively. ML models (Random Forest and Gradient Boosting) demonstrated high accuracy (R² = 0.952 ± 0.018 and 0.948 ± 0.022, respectively) in predicting biogas yield and identifying optimal pretreatment parameters. Comprehensive life cycle assessment including upstream emissions shows 49% and 37% carbon footprint reduction for solar thermal and ultrasonic systems, respectively, compared to microwave pretreatment. This work provides both experimental validation and theoretical framework for future large-scale implementation and highlights the potential of ML-driven optimization to advance sustainable sludge-to-energy conversion, offering significant implications for reducing operational costs.

Optoelectronics is advancing sustainability and energy efficiency across various industries, including renewable energy, healthcare, and environmental monitoring. This review highlights the fundamentals and mechanisms behind key optoelectronic devices such as photovoltaics, light-emitting diodes (LEDs), and sensors. It explores how advancements in photovoltaic technologies, including silicon-based, thin-film, and perovskite solar cells, are improving solar energy conversion efficiency through innovations in light absorption, charge transport, and energy band engineering. In addition, the review covers energy-efficient lighting technologies, such as LEDs, organic light-emitting diodes (OLEDs), and quantum dot-based light-emitting diodes (QLEDs), and their growing role in improving lighting systems and display technologies. Emerging trends, including flexible and wearable optoelectronic devices and integration with the Internet of Things (IoT), are also discussed, with a focus on how they contribute to more sustainable and intelligent energy solutions. Challenges like technical limitations, environmental impact, and opportunities for future research are considered, emphasizing the need for continued innovation in materials and device design. Ultimately, this article outlines the critical role of optoelectronics in shaping a sustainable, energy-efficient future across global industries, from energy and healthcare to environmental management. • Advances in perovskite materials boost photovoltaic energy efficiency. • QLEDs and LEDs drive smart lighting with enhanced color and energy savings. • Sustainable materials redefine optoelectronics for greener production. • Flexible photovoltaics enable wearable and integrated solar applications.

This study investigates the role of graphite as a support material in enhancing the catalytic activity of cobalt nickel boride (Co-Ni-B) for hydrogen generation via sodium borohydride (NaBH 4 ) hydrolysis. The graphite content was systematically varied to optimize catalytic performance, with structural and morphological analyses conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Catalytic activity was evaluated via the water displacement method, revealing that a 20 wt% graphite loading increased hydrogen production efficiency by approximately 30% compared to the unsupported catalyst. Furthermore, synthesizing the graphite-supported Co-Ni-B catalyst at 0 °C further boosted its activity. The catalyst also exhibited exceptional stability, retaining 92% of its initial activity after 5 reuse cycles, demonstrating its potential for sustainable and efficient hydrogen generation applications. • Graphite (20 wt%) boosts Co-Ni-B catalyst efficiency 30% for H₂ generation. • Synthesis at 0 °C improves catalytic performance by controlling nucleation. • Catalyst retains 92% activity after 5 cycles, ensuring high reusability. • Graphite enables heterogeneous nucleation, limiting agglomeration to boost active sites.

In this study, NiCo₂O₄-based electrode materials (NiCo 2 O 4 -B, NiCo 2 O 4 -P, NiCo 2 O 4 -O, and NiCo 2 O 4 -E) were successfully synthesized using a facile chemical oxidation method, incorporating different additives such as polyvinylpyrrolidone (PVP), oleylamine, and ethylenediaminetetraacetic acid (EDTA). All samples exhibited hexagonal platelet morphology, with NiCo₂O₄-E showing a more porous structure. Electrochemical evaluation in a three-electrode system revealed battery-type behavior with prominent redox peaks. NiCo₂O₄-E delivered the highest specific capacitance of 2254 F/g at 1 mV/s, outperforming the other variants (NiCo₂O₄-B: 1201 F/g, NiCo₂O₄-P: 1529 F/g, NiCo₂O₄-O: 1606 F/g). GCD studies confirmed its high capacity of 700 C/g at 1 A/g. Transatti analysis indicated dominant inner-surface charge contribution (93.3%), and the material exhibited the highest active site density (9.76 × 10 18 ). Although NiCo₂O₄-E retained 60% of its capacity after 5000 cycles, all samples showed nearly 100% coulombic efficiency. To evaluate practical applicability, a two-electrode solid-state asymmetric supercapacitor was fabricated using NiCo₂O₄-E as the positive electrode and activated carbon as the negative electrode. The device showed clear redox peaks in the CV profiles (0.0–1.5 V) and delivered stable GCD behavior up to 3 A/g. Notably, it retained 96% of its initial capacitance after 10,000 cycles at 3 A/g, with a consistent coulombic efficiency of 96%. Post-cycling EIS analysis confirmed improved charge transfer characteristics. These findings demonstrate that the EDTA-assisted NiCo₂O₄-E electrode exhibits excellent electrochemical performance and long-term cycling stability, making it a promising candidate for high-performance energy storage devices. • NiCo 2 O 4 was synthesized via chemical oxidation process with additives. • Enhanced charge storage achieved with battery-type electrochemical behavior. • Additives significantly influenced electrochemical performance and stability. • NiCo 2 O 4 showed the highest cyclic stability of 97% after 5000 cycles. • Transatti analysis confirmed dominant inner-surface charge storage in all samples.

Housing systems are key contributors to greenhouse gas emissions, yet environmental considerations have often remained peripheral in housing policies. In light of escalating climate challenges, this article proposes a heuristic framework to map the bidirectional relationship between housing systems and environmental outcomes. The framework shows how housing activities (e.g., construction) and attributes (e.g., size, location, price) contribute to greenhouse gas emissions and climate change, while climate change impacts housing systems. Based on this framework, the article uses recent Canadian initiatives as illustrative cases and discusses Canada’s strategies for decarbonizing construction, modifying housing attributes, and improving the connections between housing, infrastructure, and transport to move toward net-zero emissions. It highlights that significant challenges remain, including financial constraints, behavioral obstacles, and the potential exacerbation of social-spatial inequalities. The paper argues that achieving net-zero emissions requires housing policies to explicitly incorporate environmental objectives and advocates for multi-order collaboration for improving housing’s environmental outcomes.