Environmental issues, the growing demand for energy, political concerns and the medium-term depletion of petroleum has created the need for development of sustainable technologies based on renewable raw materials. Biofuels might help to meet the future energy supply demands as well as contributing to a reduction of green house gas emissions. Although this topic is highly controversial and many investigations are currently ongoing, this review is intended to give a brief overview about certain aspects of the complex biofuel issue, providing the latest update of the production and potential of biofuels in the transport sector including types of biofuel, feedstocks and technologies and some of the possible socio-economic, environmental and political implications of the widespread use of biofuels in our society.

Biodiesel is a sustainable, non-toxic, biodegradable diesel fuel substitute that can be employed in current diesel car infrastructure without major modifications in the engines. It has a significant added value compared to petroleum-based diesel, reflected in a series of improved properties including fewer carcinogenic particulate matter emissions, increased lubricity and biodegradability as well as ease of handling, transport and storage. Nevertheless, it is essential that the biodiesel life-cycle is environmentally sustainable, economically viable, and socially acceptable; views that can only be properly analysed by means of a multi-angle approach. In this contribution, we aim to provide a multidisciplinary perspective on key issues for the successful implementation of biodiesel as a petrol fuel replacement including green chemistry methods to improve production and quality, the use of energy crops and feedstocks for second-generation biodiesel as well as socio-economic studies and the importance of governmental regulatory issues.

Heterogeneous photocatalysis offer many possibilities for finding appropiate environmentally friendly solutions for many of the the problems affecting our society (i.e., energy issues). Researchers are still looking for novel routes to prepare solid photocatalysts able to transform solar into chemical energy more efficiently. In many developing countries, biomass is a major energy source, but currently such countries lack of the technology to sustainably obtain chemicals and/or fuels from it. The Roadmap for Biomass Technologies, authored by 26 leading experts from academia, industry, and government agencies, has predicted a gradual shift back to a carbohydrate-based economy. Biomass and biofuels appear to hold the key to satisfy the basic needs of our societies for the sustainable production of liquid fuels and high value-added chemicals without compromising the scenario of future generations. In this review, we aim to discuss various design routes for nanostructured photocatalytic solid materials in view of their applications in the selective transformation of lignocellulosic biomass to high value-added chemicals.

BTL-FT processes for hydrocarbon production from syngas obtained from biomass gasification are becoming increasingly trendy as suitable alternatives to produce various high quality fuels for different applications. Many investigations are ongoing to test the suitability of biomass syngas for FTS using the traditionally employed catalysts. The choice of catalysts for these processes is normally restricted to Fe and Co-based materials as they provide the best compromise between performance and price. In this perspective, we aim to provide a comparative overview of the performance between Fe and Co-based high performance FTS catalysts for hydrocarbon production via BTL-FTS processes.