Recovery of Pt and Ru from Spent Low-Temperature Polymer Electrolyte Membrane Fuel Cell Electrodes and Recycling of Pt by Direct Redeposition of the Dissolved Precursor on Carbon

Abstract

Recovery of platinum group metals (PGMs), namely, Pt and Ru, from a spent membrane electrode assembly (MEA) of a low-temperature polymer electrolyte membrane fuel cell (PEMFC) through environmentally benign and scalable processes is of significant interest and strategic importance for sustainable growth of the renewable energy industries. Here, we report such a scalable and simple process for recovery of Pt and Ru from the spent MEAs from low-temperature PEMFCs, consisting of the Pt and PtRu nanoparticles supported on carbon (Pt/C and PtRu/C) as the cathode and anode electrocatalysts, respectively. The Pt and Ru were recovered through refluxing the MEA components in a mixture of 1 M HCl and H 2 O 2 (1.5% v/v) with a dissolution efficiency >95%. Furthermore, Ru was separated from the dissolution bath in the form of Ruhydroxide precipitates, while Pt was redeposited on a carbon support to form the recycled Pt/C electrocatalyst. Unlike conventional Pt/C synthesis, where a Pt compound is used as the Pt precursor, the process uses the dissolved Pt directly and hence eliminates steps necessary to recover it in the form of a Pt compound. The synthesized Pt/C exhibits an electrochemical surface area, particle size, and durability comparable to that of the commercial counterpart. The study is of substantial interest for sustainable development of the PEMFC and other relevant industries utilizing nanoparticulate PGMs for different applications.

Review of Electro-catalysts Supported by Metal Oxides for Electrochemical Oxygen Reduction Reaction

“…특히 전기 화학 촉매 지지체는 입자크기, 비표면적 등의 물리적 특성과 촉매 안정성, 활성 등의 전기화학적 특성에 큰 영향을 미친다 [9]. 탄소 지지체는 Pt을 담지하기 위해 가장 널리 사용되는 지지체이다 [10][11][12][13]. 탄소 지지체와 Pt 높은 안정성, (4) 저렴한 비용, (5) 기공 구조 조절 등의 장점을 갖는다 [14][15][16][17].…”

Sustainable and Selective Modern Methods of Noble Metal Recycling

“…Molecular recognition tactic is also viable due to the specific interaction of Pt IV Cl 6 2− with cucurbituril forming co‐precipitate while leaving Pd II Cl 4 2− and Rh III Cl 6 3− in the solution [78] . Even simpler approaches like p H adjustment (to 13) can be applied for specific Pt and Ru containing solutions that results in Ru‐hydroxide precipitation and therefore addresses the separation problem [79] …”

“…[78] Even simpler approaches like pH adjustment (to 13) can be applied for specific Pt and Ru containing solutions that results in Ru-hydroxide precipitation and therefore addresses the separation problem. [79]…”

A Critical Assessment on Functional Attributes and Degradation Mechanism of Membrane Electrode Assembly Components in Direct Methanol Fuel Cells

“…Due to the low binding energy between the catalyst-coated membrane and the CLs, delamination of CLs often occurs throughout repetitive operations. The bonding force supplied by the direct pressing approach of CCM cannot withstand the swelling of the membrane during the operation of the DMFC, resulting in delamination [164]. A study reported that the isotropic membrane swelling (i.e., expansion coefficient difference between the CL and membrane) enhances the variance in swelling ratio with catalyst encompasses a Nafion binder, which would most likely increase electrode layer delamination [165].…”