Periodic Reporting for period 1 - low Pt loading FCCHP (Innovative fuel cell system for CHP application in Low Carbon Buildings)
Reporting period: 2016-07-01 to 2018-06-30
The amount of energy consumed by all buildings, commercial and domestic, is about 45% total consumption in the UK. Fuel cell-based CHP (combined heat and power) systems as a distributed energy system are an attractive choice, because of their both high electrical and heat efficiency and low emission. Polymer electrolyte membrane fuel cell (PEMFC) is promising for its high efficiency and zero-emission, but the high price of platinum catalysts and sluggish kinetics of oxygen reduction reaction (ORR) at cathode are the barriers for its commercialization. Platinum nanowires (Pt-NWs) supported on carbon have been used as catalysts for ORR and reported as having high activity and long durability due to their one dimension structure. Our previous work designed firstly a porous carbon matrix and grew directly pt nanowires in the pore walls of the matrix, forming a so called “Pt nanowire electrode” where the Pt nanowire morphology and distribution in the catalyst layer can be adjusted by process parameters.
The overall objective of the project is to establish scientific and engineering merits for the development of new PEMFC systems with high performance, low cost and long durability using a novel Pt-nanowire electrode technology, and based on the results to develop a low Pt loading (<0.25mgPt /cm2) electrode processes and demonstrate high-performance PEMFC system in the mCHP for low-carbon residential applications.
The overall objective of the project is to establish scientific and engineering merits for the development of new PEMFC systems with high performance, low cost and long durability using a novel Pt-nanowire electrode technology, and based on the results to develop a low Pt loading (<0.25mgPt /cm2) electrode processes and demonstrate high-performance PEMFC system in the mCHP for low-carbon residential applications.
The progress beyond the state of the art was achieved. On fundamental research, two novel processes, i.e. Pt nanoparticles (Pt seeds) in carbon matrix and wet-chemically synthesis under applied potentials, were developed and investigated on Pt nanowire (Pt-NW) growing and the electrode microstructure. The optimal novel cathode with Pt loading of 0.205 mgPt cm-2 has comparable performance to the commercial gas diffusion layer (GDE) with 0.4 mgPt cm-2. A technology for preparing the Pt-nanowire electrodes with active area 100cm2 was developed, and for the first time a prototype stack with 10-cells was assembled and preliminary tested. Finally, modelling and evaluation of energy, CO2 emission and economics for a PEMFC CHP system for application in an eco-house at University of Nottingham were carried out based on our previous Pt-nanowire electrode results. The PEMFC CHP system, serving as high global efficiency “heat and power” autonomy and backup power for emergency, operates in a load following mode with power generating on demands. The PEMFC mCHP system can reduce annual CO2 emission up to 65.99% and and bill cost to 66.74% compared with the base case scenario.
Fig. 1 showed Pt-NWs growth in the carbon matrix that a Pt-NW electrode was made. Fig. 2 presents illustration of how a fuel cell stack is prepared from carbon powder to Pt-NW electrode. Different from conventional electrode from Pt/C catalyst, Pt-NW electrode is made of carbon powder + Pt precursor, not of Pt/C catalyst, hence all Pt-NWs accessible to Oxygen and are controllable in microstructure. The Pt-NW electrode is used to prepare Membrane Electrode Assemblies (MEA), and finally MEAs are integrated into a fuel cell stack.
Fig. 1 showed Pt-NWs growth in the carbon matrix that a Pt-NW electrode was made. Fig. 2 presents illustration of how a fuel cell stack is prepared from carbon powder to Pt-NW electrode. Different from conventional electrode from Pt/C catalyst, Pt-NW electrode is made of carbon powder + Pt precursor, not of Pt/C catalyst, hence all Pt-NWs accessible to Oxygen and are controllable in microstructure. The Pt-NW electrode is used to prepare Membrane Electrode Assemblies (MEA), and finally MEAs are integrated into a fuel cell stack.
The achievements will contribute to fuel cells both in scientific theory and application technology. Potential impact includes socio-economic impact and the wider societal implications of the project. Application of the new fuel cells on the eco-buildings in Europe could also increase customer awareness and bring the low carbon or zero energy building idea to be realized.