Research in our group focuses on designing and developing new efficient heterogeneous catalytic processes that can achieve targeted conversion of fossil and biorenewable feedstocks with lower energy requirements and environmental impact. Research work involves synthesis, testing and characterisation of novel solid state materials for a wide range of applications.
Gold has been historically considered catalytically inert. However, it has become clear that suitably prepared gold nanoparticles (NPs) can show dramatic chemical activity for several key reactions in the past few years. We describe our efforts toward the development of a range of green and selective processes largely through the appropriate choice of Au catalysts coupled with the coactivation of a plethora of simple small molecules. We have focused on developing new mild and selective reductive transformations that can offer efficient alternatives to conventional Au-catalyzed hydrogenation processes. We have demonstrated Au-catalyzed selective transformation involving HCOOH activation, Au-catalyzed selective reduction involving CO and H2O activation, and Au-catalyzed C-N/C-C bond formation via alcohol activation with high selectivity. The interplay between the support and gold plays a critical role in the success of these transformations, thus highlighting the crucial importance of support in tuning the performance of supported Au NPs. Most of the reactions can tolerate a range of functional groups, and some can occur under ambient conditions.
Depending on the specific process, we propose several mechanistic scenarios that describe the plausible small-molecule-mediated reaction pathways. Additionally, we have observed an unusual reactant-promoted H2O or H2 activation over supported Au NPs, thus offering new strategies for green and facile synthesis of diverse amides and heteroaromatic nitrogen compounds. We anticipate that key insights into how simple small molecules are activated for further reaction over Au NPs should lead to a better understanding of gold catalysis and the development of new innovative PGM-free technologies.
Environmental and political problems created by our dependence on fossil fuels combined with diminishing petroleum resources are forcing society to search for renewable sources of energy. Biomass and its derivatives provide renewable alternatives to fossil-fuel resources for the sustainable production of liquid fuels and valuable chemicals. The challenge for the effective utilization of these sustainable resources is to develop costefficient processing methods for the transformation of highly functionalized carbohydrates into value-added chemicals. We have demonstrated metal (Au, Ir, Cu)-catalyzed selective conversion of bio-derived carbohydrate and glycerol into g-Valerolactone derivatives and propyle at a high selectivity.
Hydrogen (H2), an essential reagent for chemical and petrochemical industries, has been considered as one of the best candidates to satisfy the increasing demands for an efficient and clean energy. However, lack of safe, efficent and economical H2 storage technologies hinders the viability of a hydrogen-based economy. Storing H2 in chemical bonds is attractive because of the high energy density by weight of chemical fuels. In this context, one of the most promising strategies to store hydrogen entails the interconversion of H2 and CO2. This approach offers direct access to regenerative energy carriers based on waste material from the energetic use of fossil fuels, opens a possible route to convert abundantly available, inexpensive and renewable CO2 into a variety of liquid fuels, and is discussed as a potential iotion for the development of efficient sustainable energy supply chains.
We have developed an additive-free rechargeable hydrogen battery (RHB) which is based on repetitive cycles operated between aqueous formate dehydrogenation and bicarbonate hydrogenaion using highly strained Pd nanoparticles anchored on graphite oxide nanosheets as a rubust and effient solid catalyst. We believe this this designed heterogeneous metal-based catalysts hold for reversible and controlled H2 delievery, especially in the field of energy storage for sustainable energy supply.