Water shortages and climate change have brought attention to the global need for seawater desalination and renewable energy production. Currently available seawater desalination technologies are capital and energy intensive. Recent developments in microbe-mediated seawater desalination through the use of microbial desalination cells (MDCs) have a great potential to become an energy-neutral next-generation water desalination technology that utilizes wastewater as the energy source. However, the low energy conversion efficiencies and slow desalination rate of current MDC designs must be overcome if this technology is to gain broad acceptance. There are many factors that affect overall performance of the MDC, such as appropriate selection of membrane separator and its configuration, type of electrodes (both anode and cathode) as per microbe growth and chemical reaction at cathode, and so on. Our previous studies focused use of 3D N/Fe-carbon nanotube (CNT) sponge for improvement of microbial fuel cell (MFC), showing 20.3 W m-3 of maximum power density, higher than commercial Pt-carbon cloth (CC) with 12.8 W m-3. For further correlating the electronic properties of 3D N/Fe-CNT to the power density of MFC or MDC system, density functional theory (DFT) calculations using Fritz Haber Institute ab initio molecular simulation (FHI-aims) has been computed on different structures (zigzag and armchair) of pyridine-N and graphitic-N bonded to carbon atoms in the 3D N/Fe-CNT material. From pure zigzag (10, 0) and pure armchair (5, 5) CNT structures, geometry was transformed with chemical functionalization of pyridine-N defect with iron and graphitic-N in the fixed fraction algorithm. The geometry was optimized to find the effect of defects and compositional ratios of nitrogen-doping samples on the formation energy and the configuration stability. Based on the optimized geometry, binding energies, density of energy states and charge transfers were calculated for characterizing electronic properties of bifunctional CNT sponges. We found that strong interactions in the d-orbital of Fe3+ coordinated with pyridine-N and p-orbital of N atoms improved electrical conductivity and catalytic stability of the N/Fe-CNT sponge.

Electronic properties of 3D-bifunctional carbon nanotube sponge for bioelectrical system applications

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.