General Chemistry, Organic Chemistry, Inorganic Chemistry, Catalysis
9
Scopus Publications
Scopus Publications
Defective Sites Assisted N-containing NbOx Catalyzed Xylose Dehydration to Furfural Sahil Kumar, Kanika Saini, Hadi Ali, Sushil Kumar Kansal, Xiaolei Zhang, Shunmugavel Saravanamurugan Chemistryselect, 2025 Doping of heteroatoms such as N into a solid metal oxide matrix as catalysts becomes an attractive approach due to the changes in the inherent catalytic properties of the material, offering alternatives to traditional mineral acids‐catalyzed reactions in industries. With regard to this, N‐doped niobium oxide (NbOx‐D) using diethylamine was synthesized, and its catalytic activity was studied for xylose dehydration to furfural. The changes in the catalytic and characteristic properties of NbOx‐D, compared with NbOx‐D‐400 (treated under an O2 atmosphere to remove N species), were studied using various techniques. XRD and Raman analyses confirmed the structural changes in NbOx‐D due to N incorporation, based on peak shifting compared to NbOx. O2‐temperature programmed desorption (O2‐TPD) of NbOx‐D exhibited a 1.3‐fold higher number of oxygen vacancies due to N incorporation in the lattice of NbOx compared to NbOx‐D‐400. NH3‐TPD and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopic analysis corroborated the higher strength of acidic sites (Lewis and Brønsted) in NbOx‐D compared to NbOx‐D‐400. Besides, anionic nitrogen (γ‐N), based on N1s X‐ray photoelectron (XPS) spectroscopy, played a key role in the catalytic transformation of xylose to FUR, which was substantiated by the poisoning study with pyrrole (to inhibit the basic sites in NbOx‐D) during the reaction. NbOx‐D showed a FUR production rate of 49.8 µmolm−2 h−1, which was 1.6‐fold higher than NbOx‐D‐400 (31.1 µmolm−2 h−1). The NbOx‐D showed a higher catalytic activity, giving a higher FUR yield (51%) compared to commercial NbOx (<10%) under identical reaction conditions.
Crucial role of oxygen vacancies for the efficient hydrodeoxygenation of lignin-based phenolic model compounds with Ni/Ti1−xZrxO2 Hadi Ali, Neeraj Sharma, Sahil Kumar, Joris W. Thybaut, Jeroen Lauwaert, Xiaolei Zhang, Sushil Kumar Kansal, Shunmugaval Saravanamurugan Catalysis Science and Technology, 2025 Ni/Ti1−xZrxO2 with higher oxygen vacancies, stronger Lewis acidic sites and strong-metal–support interaction exhibited an enhanced hydrodeoxygenation activity to produce cyclohexane from anisole than Ni supported on corresponding mono metal oxides.
Selective Photocatalytic Oxidation of 5-Hydroxymethylfurfural using Ce doped TiO2: A Crucial Role of Defective Sites Neeraj Sharma, Hadi Ali, Shunmugavel Saravanamurugan Chemcatchem, 2024 Transforming platform compounds with conventional catalysts, such as homogeneous and heterogeneous, into valuable chemicals encounters challenges associated with entailing high temperature/pressure and reusability during the reaction. To address these challenges, photocatalysis is one of the promising approaches, especially with visible‐light‐driven photocatalysts for selective transformation. A series of cerium‐doped TiO2 (CexTiO2; x=0.5, 1, 3 and 5 wt %) are prepared via a simple coprecipitation method for the cocatalyst‐free selective oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfuran (DFF) under visible light illumination. Introducing Ce into the network to TiO2 generates impurity energy levels, reduces the band gap, and extends the spectral response range. This also causes slight distortion to the surface structure, thereby originating defective sites and various surface oxygen species, confirmed by X‐ray photoelectron spectroscopy and electron paramagnetic resonance studies. The HMF adsorption studies infer that HMF forms a surface complex with CeTiO2, facilitating the formation of ligand‐to‐metal charge transfer complex (LMCT) under visible light (~420 nm), which efficiently catalyzes the conversion of HMF (54.4 %) to DFF with a selectivity of >99 %. In‐situ DRIFTS and surface passivation studies provide insight into the interaction between HMF and surface acidic/basic sites along with hydroxyl groups of CeTiO2, which subsequently convert selectively to DFF.
Valorization of Lignocellulosic Biomass into High-Value Chemicals: Forging a Route towards the Circular Economy Mangat Singh, Sahil Kumar, Hadi Ali, Surinder Singh, Sushil Kumar Kansal Energy Materials A Circular Economy Approach, 2024 Biomass has become a critical element in meeting sustainable energy demands and driving the transition from non-renewable sources to accomplish a net-zero carbon footprint. Despite the abundant occurrence of biomass in nature, effectively converting it poses significant challenges. Furthermore, the segregation of biomass components holds the promise of generating environmentally friendly chemicals with versatile applications in the chemical industry. This not only minimizes waste generation but also reduces our dependence on fossil-based resources. In this chapter, we explore the potential of lignocellulosic biomass as a sustainable carbon-based resource and the processes necessary for its utilization. Additionally, we delve into current market trends and production strategies for high-value chemicals derived from biomass.
Enhancing the anisole hydrodeoxygenation activity over Ni/Nb2O5−x by tuning the oxophilicity of the support Hadi Ali, Tom Vandevyvere, Jeroen Lauwaert, Sushil Kumar Kansal, Maarten K. Sabbe, Shunmugavel Saravanamurugan, Joris W. Thybaut Catalysis Science and Technology, 2023 Ni/Nb2O5-H, preparedviathe hydrolysis method, possesses a higher number of oxygen vacancies and metal-support interface than Ni on commercial Nb2O5(Ni/Nb2O5-C), resulting in enhanced activity and selectivity towards deoxygenated products.
Impact of oxygen vacancies in Ni supported mixed oxide catalysts on anisole hydrodeoxygenation Hadi Ali, Tom Vandevyvere, Jeroen Lauwaert, Sushil Kumar Kansal, Shunmugavel Saravanamurugan, Joris W. Thybaut Catalysis Communications, 2022 The hydrodeoxygenation (HDO) activity of anisole has been investigated over Ni catalysts on mixed metal oxide supports containing NbZr and TiZr in 1:1 and 1:4 ratios. XRD patterns indicate the incorporation of Ti (or Nb) into the ZrO2 framework. XPS and oxygen pulse chemisorption analyses reveal that Ni/Ti1Zr4 and Ni/Nb1Zr4 possessed more oxygen vacancy sites than Ni/Ti1Zr1 and Ni/Nb1Zr1, respectively. Correspondingly, the HDO activity of Ni/Ti1Zr4 and Ni/Nb1Zr4 was higher with an anisole conversion up to 30.7 and 34.4%, with high selectivity towards benzene (up to 64.7 and 63.3%), compared to corresponding Ni/Ti1Zr1 and Ni/Nb1Zr1 catalysts.
Alumina-Supported Alkali and Alkaline Earth Metal-Based Catalyst for Selective Decarboxylation of Itaconic Acid to Methacrylic Acid Hadi Ali, Sushil Kumar Kansal, Shunmugavel Saravanamurugan Chemistryselect, 2021 The present study focuses on selective decarboxylation of itaconic acid (IA) to methacrylic acid (MAA) using alkali and alkaline earth metals (Na, K, Mg and Ca) supported on Al2O3, prepared by incipient wet impregnation approach. The parent Al2O3, predominantly composed of the boehmite phase, is entirely transformed to γ‐Al2O3 phase upon impregnating calcium, based on XRD analysis, and this is not the case for other metals employed in this study. FTIR analysis corroborates the complete decomposition of nitrate precursor in the case of calcium than other metals (Na, K and Mg). UV‐Vis analysis using diffused reflectance mode suggests that Ca incorporated on to the Al2O3 matrix. Among the catalysts employed, the highest yield of methacrylic acid (MAA) (46.7 %) is achieved with 5 wt % Ca/Al2O3 at 250 °C, 20 bar N2 after 3 h. Moreover, 15.1 % of α‐hydroxyisobutyric acid (α‐HIBA), a hydrated product of MAA, is also obtained, and thus, the combined yield of MAA and α‐HIBA is 61.8 %. The selective decarboxylation of IA to MAA/α‐HIBA can be correlated with the number of basic sites present in the 5 wt % Ca/Al2O3, which possess the highest number of basic sites than other catalysts.
Sustainable production of sorbitol-a potential hexitol Sahil Kumar, Hadi Ali, Sushil Kumar Kansal, Ashok Pandey, Shunmugavel Saravanamurugan Biomass Biofuels Biochemicals Recent Advances in Development of Platform Chemicals, 2019
