New energy is one of the pillar industries for sustainable development in the 21st century, and fuel cells are one such industry. Phosphoric acid fuel cells (PAFC), proton exchange membrane fuel cells (PEMPC), and methanol fuel cells (DMFC) all use Pt-C, Pt-Co-Cr, Pt-Co-Fe, Pt-Ru, Pt-Ni, and Pd-C as catalytic electrodes to directly convert combustible gases into electrical energy.
Compared to other energy sources, although the economic viability of fuel cells has been questioned, their advantages, such as low operating temperature, high energy conversion efficiency, abundant fuel sources, no environmental pollution, and gradually decreasing platinum usage (from 14 g/kW in 1994 to 0.5 kW in 2008, and even 0.2 g/kW in laboratory settings), have led to continuous research and application studies in areas such as small portable power sources, home power stations, automotive power, and submarine power.
The core component of a PEMFC battery is the membrane electrode assembly, which consists of an anode diffusion layer, an anode porous carbon fiber layer, an anode catalytic layer, an electrolyte membrane, a cathode catalytic layer, a cathode porous carbon fiber layer, and a cathode diffusion layer laminated together. The anode and cathode catalyst layers contain Pt (or Pd) at a concentration of 0.15-0.19 mg/cm². Waste membrane electrodes can be treated by incineration, chemical dissolution of organic compounds to strip the catalyst, crushing followed by magnetic separation, etc., to recover the Pt (or Pd).
