Direct synthesis of Pt-free catalyst on gas diffusion layer of fuel cell and usage of high boiling point fuels for efficient utilization of waste heat. (1st November 2017)

• Record Type: Journal Article
• Authors: Nandan, Ravi; Goswami, Gopal Krishna; Nanda, Karuna Kar
• Is Part Of: Applied energy. Volume 205(2017)
• Page Start: 1050
• Page End: 1058
• Publication Date: 2017-11-01
• Subjects: Doped carbon nanotubes -- Gas diffusion layer -- Electrocatalyst -- Oxygen reduction reaction -- Fuel cell -- Waste heat; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2017.08.118
• Languages: English
• ISSNs: 0306-2619

Abstract

Graphical abstract: Direct-grown boron-doped carbon nanotubes on gas-diffusion layer as efficient Pt-free cathode catalyst for alcohol fuel cells, high boiling point fuels used to obtain hot fuels for the enhancement of cell performance that paves the way for the utilization of waste heat. Highlights: One-step direct synthesis of boron-doped carbon nanotubes (BCNTs) on gas diffusion layer (GDL). Home built fuel-cell testing using BCNTs on GDL as Pt-free cathode catalyst. BCNTs exhibit concentration dependent oxygen reduction reaction and the cell performance. Effective utilization of waste heat to raise the fuel temperature. Fuel selectivity to raise the fuel temperature and the overall performance of the fuel cells. Abstract: Gas diffusion layers (GDL) and electrocatalysts are integral parts of fuel cells. It is, however, a challenging task to grow Pt-free robust electrocatalyst directly on GDL for oxygen reduction reaction (ORR) – a key reaction in fuel cells. Here, we demonstrate that boron-doped carbon nanotubes (BCNTs) grown directly on gas-diffusion layer (which avoid the need of ionomer solution used for catalyst loading) can be used as efficient Pt-free catalyst in alcohol fuel cells. Increase in boron concentration improves the electrochemical ORR activity in terms of onset and ORR peak positions, half-wave potentials and diffusion-limited current density that ensure the optimization of the device performance. The preferential 4e − pathway, excellent cell performance, superior tolerance to fuel crossover and long-term stability makes directly grown BCNTs as an efficient Pt-free cathode catalyst for cost-effective fuel cells. The maximum power density of the fuel cell is found to increase monotonically with boron concentration. In addition to the application of BCNTs in fuel cell, we have introduced the concept of hot fuels so that waste heat can effectively be used and external power sources can be avoided. The fuel is passed through a hot bath for the realization of hot fuel which eventually increases the operating temperature of the cell (for example: 60 °C for methanol and 80 °C for ethyleneglycol, avoids the requirement of heating arrangement) and hence, the performance. Overall, different strategies to design ultimate fuel cells for their commercial adoption and effective utilization of waste heat have been outlined.