Dr Ihtasham (Hammy) Salam

Postgraduate Research Student

Academic and research departments

School of Chemistry and Chemical Engineering.


My research project


Terry R. Willson, Carlos A. Giron Rodriguez, Qiucheng Xu, Jordan Frow, Fabrizia Foglia, Keenan Smith, Ravikumar Ravikumar, Mohanraj Vinothkannan, Najet Mahmoudi, Ihtasham Salam, Arun Prakash Periasamy, Daniel Keith Whelligan, Mohamed Mamlouk, Hungyen Lin, Brian Seger, John Varcoe (2023)Radiation-grafted anion-exchange membranes for CO 2 electroreduction cells: an unexpected effect of using a lower excess of N -methylpiperidine in their fabrication, In: Journal of Materials Chemistry A: materials for energy and sustainability11(38)20740 Royal Society of Chemistry

Giron Rodriguez et al. [ACS Sustainable Chem. Eng., 2023, 11, 1508] previously showed that radiation-grafted anion-exchange membranes containing N-benzyl-N-methylpiperidinium headgroups (MPIP-RG-AEM) are promising for use in CO2 electrolysis (cf. commercial and other RG-AEM types). For a more sustainable synthesis, MPIP-RG-AEMs have now been fabricated using a reduced 1.1 times excess of amine reagent (historically made using >5 times excess). A resulting RG-AEM promisingly had a bulk amination level that was comparable to those made with the traditional large excess. Unexpectedly, however, it had a significantly reduced water content, with two further batches showing that this observation was repeatable (and reproducible via measurements collected on a single batch using different techniques in different labs). The ionic conductivities of the RG-AEM made with a controlled 1.1 excess of amine were also lower, with higher activation energies. Terahertz time-domain spectroscopy measurements showed that the lower water uptake RG-AEMs, made with the 1.1 amine excess, contained smaller amounts of bulk water relative to bound water (a repeatable observation with different counter-anions). This lack of bulk water, yielding reduced water diffusion coefficients, led to a change in the water management when such RG-AEMs were tested in CO2 electrolysis cells, with significantly affected in situ performances. Small angle scattering data (X-ray and neutron) indicated that MPIP-RG-AEM fabrication with the 1.1 excess of amine reduced the size of the amorphous lamella domains on hydration, and this change is suspected to be the cause of the lower water uptakes and swelling. The finding that chemically similar AEMs can have significantly different hydration properties is potentially important to all ion-exchange membrane users and developers (beyond the CO2 electrolysis scope of this study).

John Varcoe, Rachida Bance-Souahli, Arup Chakraborty, Mehdi Choolaei, Carol Crean, Carlos Giron Rodriguez, Bjørt Óladóttir Joensen, Judy Lee, Arun Prakash Periasamy, Ihtasham Salam, Brian Seger, Daniel Whelligan, Terrence Willson (2022)The Latest Developments in Radiation-Grafted Anion-Exchange Polymer Electrolytes for Low Temperature Electrochemical Systems, In: Meeting abstracts (Electrochemical Society)MA2022-01(35)pp. 1443-1443 The Electrochemical Society, Inc
Kanika Aggarwal, Nansi Gjineci, Alexander Kaushansky, Saja Haj-Bsoul, John C. Douglin, Songlin Li, IHTASHAM SALAM, Sinai Aharonovich, JOHN VARCOE, Dario R. Dekel, Charles Diesendruck (2022)Isoindolinium Groups as Stable Anion Conductors for Anion-Exchange Membrane Fuel Cells and Electrolyzers, In: ACS Materials Au2(3)pp. 367-373 APS

Anion-exchange membrane (AEM) fuel cells (AEMFCs) and water electrolyzers (AEMWEs) have gained strongattention of the scientific community as an alternative to expensive mainstream fuel cell and electrolysis technologies. However, in the high pH environment of the AEMFCs and AEMWEs, especially at low hydration levels, the molecular structure of most anion-conducting polymers breaks down because of the strong reactivity of the hydroxide anions with the quaternary ammonium (QA) cation functional groups that are commonly used in the AEMs and ionomers. Therefore, new highly stable QAs are needed to withstand the strong alkaline environment of these electrochemical devices. In this study, a series of isoindolinium salts with different substituents is prepared and investigated for their stability under dry alkaline conditions. We show that by modifying isoindolinium salts, steric effects could be added to change the degradation kinetics and impart significant improvement in the alkaline stability, reaching an order of magnitude improvement when all the aromatic positions are substituted. Density functional theory (DFT) calculations are provided in support of the high kinetic stability found in these substituted isoindolinium salts. This is the first time that this class of QAs has been investigated. We believe that these novel isoindolinium groups can be a good alternative in the chemical design of AEMs to overcome material stability challenges in advanced electrochemical systems.

Rong Ren, Xiaojiang Wang, Hengquan Chen, Hamish Andrew Miller, Ihtasham Salam, John Robert Varcoe, Liang Wu, Youhu Chen, Hong-Gang Liao, Ershuai Liu, Francesco Bartoli, Francesco Vizza, Qingying Jia, Qinggang He (2020)Reshaping the Cathodic Catalyst Layer for Anion Exchange Membrane Fuel Cells: From Heterogeneous Catalysis to Homogeneous Catalysis, In: Angewandte Chemie (International ed.)60(8)pp. 4049-4054 Wiley / Gesellschaft Deutscher Chemiker

In anion exchange membrane fuel cells, catalytic reactions occur at a well-defined three-phase interface, wherein conventional heterogeneous catalyst layer structures exacerbate problems, such as low catalyst utilization and limited mass transfer. We developed a structural engineering strategy to immobilize a molecular catalyst tetrakis(4-methoxyphenyl)porphyrin cobalt(II) (TMPPCo) on the side chains of an ionomer (polyfluorene, PF) to obtain a composite material (PF-TMPPCo), thereby achieving a homogeneous catalysis environment inside ion-flow channels, with greatly improved mass transfer and turnover frequency as a result of 100 % utilization of the catalyst molecules. The unique structure of the homogeneous catalysis system comprising interconnected nanoreactors exhibits advantages of low overpotential and high fuel-cell power density. This strategy of reshaping of the catalyst layer structure may serve as a new platform for applications of many molecular catalysts in fuel cells.

Hamish A. Miller, Maria V. Pagliaro, Marco Bellini, Francesco Bartoli, Lianqin Wang, Ihtasham Salam, John Varcoe, Francesco Vizza (2020)Integration of a Pd-CeO2/C anode with Pt and Pt-free cathode catalysts in high power density anion exchange membrane fuel cells, In: ACS applied energy materials3(10)pp. 10209-10214 Amer Chemical Soc

Recent advances in developing high-performance anion exchange membranes (AEMs) for fuel cell (AEMFC) applications enable catalyst developers to investigate and test cheaper and/or more sustainable materials under operando fuel cell conditions. In this article, we integrate a high-performance Pd-CeO2/C hydrogen oxidation reaction (HOR) catalyst into AEMFCs in combination with different Pt and Pt-free cathodes. A H-2/O-2 AEMFC peak power performance of 2 W cm(-2) at 80 degrees C is obtained when using a Pt/C cathode (2 A cm(-2) is achieved at a cell voltage of 0.6 V), which translates to 1 W cm' peak power density (0.7 A cm(-2) is achieved at 0.6 V) at 60 degrees C with the switch to a cheap, critical raw material (CRM)-free Fe/C cathode catalyst.

John Varcoe, Ihtasham Salam, Arup Chakraborty, Mehdi Choolaei, Rachida Bance-Souahli, Terrence Willson (2022)(Invited) Radiation-Grafted Anion-Exchange Membranes for Reverse Electrodialysis (RED): The Effect of Changing Functional Groups on Key Properties, In: Meeting abstracts (Electrochemical Society)MA2022-02(43)pp. 1611-1611 The Electrochemical Society, Inc
Min Wang, Huixin Zhang, Gnanavel Thirunavukkarasu, Ihtasham Salam, John R. Varcoe, Peter Mardle, Xiaoying Li, Shichun Mu, Shangfeng Du (2019)Ionic Liquid-Modified Microporous ZnCoNC-Based Electrocatalysts for Polymer Electrolyte Fuel Cells, In: ACS Energy Letters4(9)pp. 2104-2110 American Chemical Society

Non-platinum group metal (non-PGM) oxygen reduction reaction (ORR) catalysts have been widely reported, but their application in proton exchange membrane fuel cells (PEMFCs) is challenging because of their poor performance in acidic environments. Here, [BMIM][NTf₂] ionic liquid (IL) modification of microporous ZnCoNC catalysts (derived from ZIF-ZnCo) is investigated to study their behavior in PEMFCs and to elucidate the catalytic mechanisms in practical operation. The high O₂ solubility of ILs enhances the utilization of active sites with porous ZnCoNC, and their hydrophobic nature facilitates the water transport during fuel cell operation. The half-cell measurement in aqueous HClO₄ shows that with the 20 wt % IL modification, the electron-transfer number increases from 2.58 to 3.88, approaching the desired 4-electron-transfer ORR. The power density obtained shows 140% improvement in single-cell PEMFC tests. The catalyst also yields an interesting performance in alkaline anion-exchange membrane fuel cells.

Arup Chakraborty, Ihtasham Salam, Mehdi Choolaei, Judy Yu-Ting Lee, Carol Crean, Daniel Keith Whelligan, Rachida Bance-Soualhi, John Varcoe (2023)Changes in permselectivity of radiation-grafted anion-exchange membranes with different cationic headgroup chemistries are primarily due to water content differences †, In: Materials Advances4pp. 2099-2105 Royal Society of Chemistry

In a prior paper [Bance-Soualhi et al., J. Mater. Chem. A, 2021, 9, 22025], we showed that the crosslinking of radiation-grafted anion-exchange membranes (RG-AEM) was necessary to obtain high enough apparent permselectivities for use in applications such as (reverse)electrodialysis. However, a separate result in this prior study suggested that comparable AEMs (similar ion-exchange capacity, IEC, and backbone chemistry) with different cationic headgroups may yield different balances between permselectivity and conductivity. This short follow-up study compares the permselectivities and Cl À conductivities of a series of non-crosslinked RG-AEMs with either aliphatic quaternary ammonium headgroups (N-benzyl-N-methylpiperidinium, MPIP, and benzyltrimethylammonium, TMA) or aromatic cationic headgroups (N-benzylpyridinium, PYR, or 1-benzyl-2,3-dimethylimidazolium, DMI). We show that a change in the headgroup chemistry modified the permselectivity-conductivity balance of the RG-AEM, but this was primarily due to the different headgroups inducing varying intrinsic water contents: higher water content RG-AEMs yield lower permselectivites. As also expected from this water content observation, higher IEC variants yielded RG-AEMs with lower permselectivities. The addition of N,N,N 0 ,N 0-tetramethylhexane-1,6-diamine-(TMHDA)-based ionic crosslinking to a DMI-based RG-AEM also raised permselectivity, confirming the observation of the prior study also applies to aromatic headgroup RG-AEMs. In summary, high IEC AEMs containing imidazolium-type headgroups along with an optimal amount of ionic crosslinking could be promising and warrant more study (i.e. a comparison of RG-AEMs with cheaper, more scalable non-RG-analogues that contain these attributes).