Orazio Barbera

This study evaluates the feasibility of a hybrid hydrogen fuel cell–battery power supply for lower limb assistive exoskeletons. The objective is to determine whether this architecture can provide a realistic alternative to conventional lithium‐ion batteries in terms of autonomy, mass, and responsiveness to dynamic loads. Starting from a gait‐cycle power profile, the electrical demand of a six‐joint exoskeleton is estimated for a reference scenario of 10 000 assisted steps per day, corresponding to approximately 170 Wh. A battery‐only configuration and a hybrid fuel cell–battery system are then sized and compared at first‐order system‐level. The results indicate that, under the current technological assumptions, the hybrid configuration is heavier than the battery‐only solution while providing a lower driving range, demonstrating that it offers no practical advantage. A sensitivity analysis identifies gravimetric hydrogen storage capacity as the dominant parameter affecting system performance, whereas improvements in fuel cell stack specific power have a more limited effect. Increasing the storage capacity of the selected metal‐hydride system from 1.5 to 3 wt% would substantially reduce total mass and increase specific energy, making hybrid architectures more competitive for wearable robotics.

Infrared (IR) thermography is increasingly recognized as a powerful diagnostic tool in the field of fuel cells, where technical and economic challenges hinder large-scale diffusion. This study presents two novel methodologies based on IR thermography as a tool to address two critical aspects of fuel cells: the uniformity of catalyst deposition on the electrode surface and the detection of hydrogen leaks to the ecternal environment. The first method is based on the exothermic reaction of a reactive H2/N2 gas mixture on the catalyzed electrode surface, where the thermal response is correlated with local platinum content. The second method enables localization of hydrogen leaks based on the heat generated by the catalytic reaction between hydrogen and ambient air on an active tracer surface. Both methodologies are non-destructive, cost-effective, automatable and suitable for quality assurance in both production and operational contexts. These results expand the diagnostic capabilities of IR thermography and support its integration into next-generation fuel cell development and manufacturing workflows.

Hydrogen leakage in Proton Exchange Membrane (PEM) fuel cells poses critical safety, efficiency, and operational reliability risks. This study introduces an innovative infrared (IR) thermography-based methodology for detecting and quantifying hydrogen leaks towards the outside of PEM fuel cells. The proposed method leverages the catalytic properties of a membrane electrode assembly (MEA) as an active thermal tracer, facilitating real-time visualisation and assessment of hydrogen leaks. Experimental tests were conducted on a single-cell PEM fuel cell equipped with intact and defective gaskets to evaluate the method’s effectiveness. Results indicate that the active tracer generates distinct thermal signatures proportional to the leakage rate, overcoming the limitations of hydrogen’s low IR emissivity. Comparative analysis with passive tracers and baseline configurations highlights the active tracer-based approach’s superior positional accuracy and sensitivity. Additionally, the method aligns detected thermal anomalies with defect locations, validated through pressure distribution maps. This novel, non-invasive technique offers precise, reliable, and scalable solutions for hydrogen leak detection, making it suitable for dynamic operational environments and industrial applications. The findings significantly advance hydrogen’s safety diagnostics, supporting the broader adoption of hydrogen-based energy systems.

The World Economic Forum’s Global Risks Report 2022 identifies climate change as a paramount threat to humanity

Tandem photoelectrochemical cells (PECs) are devices useful for water splitting (WS) with the production of oxygen at the photoanode (PA) and hydrogen at the photocathode (PC) by adsorbing more than 75% of the solar irradiation; a portion of the UV/Vis direct solar irradiation is captured by the PA and a diffused or transmitted IR/Vis portion by the PC. Herein, Ti-doped hematite (PA) and CuO (PC) were employed as abundant and non-critical raw semiconductors characterised by proper band gap and band edge banding for the photoelectrochemical WS and absorption of sunlight. The investigation of inexpensive PEC was focused on the scalability of an active area from 0.25 cm² to 40 cm² with a rectangular or square shape. For the first time, this study introduces the novel concept of a glass electrode membrane assembly (GEMA), which was developed with an ionomeric glue to improve the interfacial contact between the membrane and photoelectrodes. On a large scale, the electron–hole recombination and the non-optimal photoelectrodes/electrolyte interface were optimized by inserting a glass support at the photocathode and drilled fluorine tin oxide (FTO) at the photoanode to ensure the flow of reagents and products. Rectangular 40 cm² PEC showed a larger maximum enthalpy efficiency of 0.6% compared to the square PEC, which had a value of 0.37% at a low bias-assisted voltage (−0.6 V). Furthermore, throughput efficiency reached a maximum value of 1.2% and 0.8%, demonstrating either an important effect of the PEC geometries or a non-significant variation of the photocurrent within the scalability.