Zeeshan Nazir, Khalil Ul Rehman, Iftikhar Hussain, Ishfaq Majeed Mir, Raqeeba Aziz & Mohammad Aslam*

Abstract: Diminishing levels of crude oil are hinting towards an inevitable global shortage of fuels and it is imperative to look for the alternate sources of crude oil at this hour. Lignocellulosic biomass (LCB) emerges as a neutral carbon footprint resource rather than just an organic solid waste. LCB is the most abundant renewable bioresource material on Earth, primarily made up of cellulose, hemicellulose, and lignin, firmly associated with each other. It is a key alternate that could be used for producing various value-added chemicals and biofuels through thermochemical methods of conversion. However, bio-oil produced from LCB has undesirable properties like low heating value, chemical instability, high, viscosity and corrosivity, limiting its use as a drop-in fuel, thus, needs upgrading. This study explores the recent advancements in the thermochemical conversion technologies, including catalyst effects, innovative technologies, environmental impact and potential commercialization. By highlighting the present state of the field and identifying potential future directions, this chapter aims to provide a comprehensive overview of the advancements and challenges in converting lignocellulosic biomass into bio-crude. Additionally, the chapter discusses future directions for this technology.

Zeeshan Nazir, Khalil Ul Rehman, Iftikhar Hussain, Ishfaq Majeed Mir, Raqeeba Aziz & Mohammad Aslam*

Abstract: Diminishing reserves of crude oil across the globe has led to a shift towards the alternate methods of energy production in order to meet the energy demands for the growing population of the world. Amongst many areas, bio-crude production from 1st, 2nd, 3rd, and 4th generation biomasses is a promising one because of its versatility, mass availability of potential feedstocks, and sustainability. Biomasses are converted through different chemical, bio-chemical and thermo-chemical processes into biocrude and other value-based necessary products. However, this biocrude oil needs to be further upgraded in order to be used as a drop in fuel. Not all biocrude produced from these methods and resources has the same standard properties that are required for it to be used as a drop in fuel. Standard requirements like viscosity, density, stability, energy density, combustion, thermal and elemental properties etc. depend on the type of feedstock used and thus need to be checked and evaluated to produce finished fuels that comply with regulated specifications. This chapter deals with the analytical techniques employed for the physical, chemical and elemental analysis of bio fuels. Moreover, fuel property evaluation and international standards & specifications are also discussed to compare the quality of the bio fuels with the regulatory standards.

Romana Khanam,  Afshana Hassan,   Zeeshan Nazir  and  Manzoor Ahmad Dar*

Designing efficient and low cost electrocatalysts for the reduction of CO2 to valuable chemicals is a sustainable way of mitigating and balancing its concentrations in the atmosphere which is essential for avoiding effects like climate change and global warming. Herein by means of systematic density functional theory simulations, we investigate the effect of support on the activity/selectivity of Ni based single atom catalyst (SAC) supported on GaN, MoS2, Mo2C, g-C2N and graphyne monolayers towards CO2 activation and reduction to different C1 products. Our results reveal that the Ni SAC strongly binds on all the monolayer supports forming highly stable catalysts. The type of support plays a strong role in tuning the binding and activation of CO2 with Ni SAC supported on GaN and MoS2 monolayers showing the highest CO2 binding energies. Rigorous and in-depth electronic structure analysis reveals that the CO2 binding energy on these catalysts can be successfully rationalized in terms of electronic properties such as the d-band centre and integrated crystal orbital Hamilton populations. Moreover, the computed reaction pathways using the computational hydrogen electrode model indicate that the Ni SAC supported on the GaN monolayer can catalyse the CO2 reduction to CH3OH at a record low limiting potential of −0.28 V whereas the Ni SAC supported on the MoS2 monolayer catalyses CO2 reduction to HCOOH at a limiting potential of –0.42 V. Thus, our results show that the nature and type of support plays critical role in modulating the CO2 reduction activity/selectivity on these catalysts and provide insightful guidance for effective catalyst design for CO2 conversion to value added chemicals.