The indoor air quality (IAQ) is paramount to the existence of humans considering the amount of time spent indoors. The indoor pollutant levels may be 100 times the levels outdoors. The indoor pollutants need to be considered to enhance better IAQ. This study determined the emission factors of carbon monoxide (CO) emitted from a standby electricity generator (SEG). It evaluated the impacts of CO concentrations on indoor air quality and identified appropriate ways to mitigate the CO concentrations. The indoor CO concentration was determined by simulating a number of scenarios of SEG operated outdoor using a Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure (IAQX) model. Hourly measurements of mean CO concentrations in the ambient environment and wind speed were conducted for four weeks in four field locations. The emission rate of CO from the standby electricity generator was measured. The CO concentration from SEG was 2.4289 × 10⁴ mg/m³, a very high CO concentration. The CO emission factors were obtained as 2.2366 × 10³ kg/m³ of fuel consumed and 9.5411 × 10⁶ kg/hr of activity. High CO concentrations were obtained in microenvironments from the scenarios 1.28 × 10⁴ mg/m³, 4.78 × 10³ mg/m³, 4.79 × 10⁴ mg/m³ and 9.58 × 10⁴ mg/m³. The results showed that a high air exchange rate allowed CO concentrations to decay fast while low air exchange rates created an accumulation of CO concentrations indoor.

The global transition toward sustainable energy systems has intensified interest in renewable hydrogen as a key pathway for reducing greenhouse gas emissions and decarbonizing hard-to-abate sectors. This review critically examines major renewable hydrogen production routes, including alkaline water electrolysis (AWE), proton exchange membrane (PEM) electrolysis, solid oxide electrolysis cells (SOEC), biomass-based conversion, photoelectrochemical water splitting, and biological processes. Particular emphasis is placed on recent advances in catalytic and electrocatalytic materials and their influence on hydrogen-production efficiency, durability, operating flexibility, cost, and scalability. Noble-metal and non-noble-metal catalyst systems, electrode materials, and emerging catalytic strategies are discussed in relation to their suitability for different hydrogen-production technologies and renewable-energy operating conditions. The review further compares the major production pathways in terms of technological maturity, system efficiency, scalability, and compatibility with intermittent renewable energy. Key limitations associated with catalyst degradation, critical-material dependence, hydrogen storage, infrastructure development, and system integration are critically assessed. Current research gaps include the need for more durable and earth-abundant catalysts, improved long-term performance under realistic operating conditions, and stronger integration between materials development and system-level techno-economic requirements. Overall, this review highlights the importance of linking catalytic innovation with electrolyzer design, renewable-energy integration, infrastructure readiness, and sustainability considerations to enable economically viable and scalable renewable hydrogen production.

Surfactants are amphiphilic compounds that enable the mixing of immiscible substances like oil and water by reducing interfacial tension. However, their application in Enhanced Oil Recovery (EOR) is limited by issues such as toxicity, poor biodegradability, and dependence on edible oils, which can compromise food security. This study focused on synthesizing a non-ionic surfactant from neem (Azadirachta indica) seed oil—a non-edible, biodegradable alternative. Neem seeds were collected from Bayero University Kano, dried for six weeks, and subjected to proximate and Fourier Transform Infrared Spectroscopy (FTIR) analyses. Proximate analysis revealed 28.76% moisture, 14.44% oil/fat, 16.67% protein, and 5.1% ash. FTIR analysis identified key functional groups such as O-H, C-H, and C?N stretching. Oil extraction was carried out using Soxhlet apparatus with 800 ml of n-hexane at 65°C for 1.2 hours, yielding 23% oil, consistent with literature values. The extracted oil showed an acid value of 1.88 mg KOH/g and a saponification value of 184.8 mg KOH/g, indicating suitability for surfactant synthesis. Further FTIR analysis confirmed the presence of functional groups like C-H, C=O, CH2, CH3, C-O, and -(CH2)-n. A non-ionic surfactant was synthesized by reacting 10 ml of neem oil with 5 g NaOH at 80 °C for 2.5 hours, along with 50 ml of distilled water under continuous stirring. FTIR analysis of the product revealed characteristic O-H, COO?, and C-O functional groups, confirming successful surfactant formation. The findings support neem oil as a viable, sustainable surfactant source for EOR applications.