Photocatalytic methanation membrane: A low-energy, low-resource route to biomethane expansion for net-zero

Decarbonising heat and vehicle fuels are the most difficult challenges in delivering net-zero for the UK by 2050. Biomethane already has the potential to replace 18% of natural gas consumption. Production capacity is set to grow further through the UK Green Gas Support Scheme (2021-) to deliver additional carbon savings of 21.6MtCO₂E. The UK water industry is a primary producer of biogas in the UK and has delivered the World’s first sector wide commitment to deliver net-zero by 2030. Increasing biomethane production is one of the key options to delivering this ambitious strategy, where biomethane can also be used as a low carbon alternative to vehicle fuels.       

One method to increase biomethane production is to transform the carbon dioxide present in biogas to methane (‘methanation’). This can improve methane production capacity from existing installations by almost 100%, which can reduce the cost of expanding capacity and accelerate the transition to net-zero.   

We are therefore developing an innovative membrane technology to facilitate photocatalytic methanation for the efficient transformation of CO₂ to methane. The membrane provides selective transport of CO₂ from biogas into water comprising a concentrated photocatalyst slurry which uses light to excite electrons at the catalyst surface. The catalyst reacts with water to create the hydrogen needed for reaction and mediates the transformation of CO₂ (and H₂) to methane. The process will permit biomethane production, and CO₂ methanation within one technology, which does not rely on the costly production of hydrogen, or expensive catalysts for processing. This unique configuration therefore creates a low-resource route to biomethane expansion which can use renewable power to create a highly attractive carbon negative biomethane fuel.

This PhD is funded by EPSRC and four major UK Water Utilities (Anglian, Northumbrian, Severn Trent and Thames water).

The project will: (i) study the mass transport of CO₂ across the membrane into concentrated catalytic slurries; (ii) develop hydrodynamic conditions that can enhance CO₂ transformation by controlling the size and shape of catalytic aggregates, and their interaction with light; (iii) relate operating conditions to the rate of transformation, product formation and yield to improve methanation efficiency; and (iv) develop a business case for investment. Training will be provided, and there will also be an opportunity to gain experience in the design and construction of experimental technologies, as well as undertaking their final evaluation.

By the end of the project, the successful candidate will by leading delivery of the enabling science for this disruptive technology, which offers substantive industrial and environmental benefit, providing a unique skillset in an emerging platform technology that will see use in numerous applications. The researcher will be based at Cranfield University to take advantage of their world class experimental research facilities and will work in collaboration with industry partners throughout the technology development, providing an opportunity for direct relevant industrial experience. UK and international travel are expected, to disseminate scientific progress to industry and academic audiences.

In addition to an extensive transferrable skills programme on offer at Cranfield, the candidate will work with their academic supervisors to tailor a personal development plan based on experience, and career aspirations. Specific laboratory skills training will be provided. Our aspiration is to train leading research talent, with advanced analytical and communication skills, that will differentiate our finishing candidates from their peers to maximise their success in academia and industry.