Assessment of commercial micro-machined hydrogen sensors performance metrics for safety sensing applications

• Evaluation of sensing metrics for micro-machined H2 (TC & MOX) sensors.
• The influence flow rate on the final indication and sensors response is studied.
• Micro-machined TC sensor show improvements over the conventional counterpart.
• Micro-machined MOX sensor showed some degradation in performance.

Hydrogen sensors are increasingly recognized as safety enhancing components in applications where hydrogen is used as a clean energy carrier. The availability of low-cost, reliable, high performance hydrogen sensors is critical for facilitating the widespread and safe deployment of hydrogen systems. Accordingly, new sensing element designs based on advanced manufacturing techniques are being developed. Using micro-machining techniques, miniaturized versions of conventional hydrogen gas sensing elements have already been introduced in the market, with the promise of low-cost and high performance sensing metrics. An assessment of commercial micro-machined sensing elements relative to their conventional counterpart is presented in this paper. The results show that although some performance improvements were observed for commercial micro-machined sensors relative to their conventional counterparts, some models of micro-machined sensors were plagued with significant performance degradation. Furthermore, actual sensor performance, as determined by laboratory assessment often did not meet the manufacturer's published specifications. This work verifies the sensing metrics improvements brought by the micro-technology as well as its shortcomings for guiding the end-user safety applications.