Conjugated nanomaterials for solar fuel production

Photocatalytic hydrogen production from water has the potential to fulfil future energy needs by producing a clean and storable fuel. In recent years polymer photocatalysts have attracted significant interest in an attempt to address these challenges. One reason organic photocatalysts have been considered an attractive target is their synthetic modularity, therefore, the ability to tune their opto-electronic properties by incorporating different building blocks. A wide range of factors has been investigated and in particular nano-sized particles have found to be highly efficient due to the size effect resulting from the ability of these to increase the number of charges reaching catalytic sites

Conjugated polymer donor-molecular acceptor nanohybrids for photocatalytic hydrogen evolution.

A library of 237 organic binary/ternary nanohybrids consisting of conjugated polymers donors and either fullerene or non-fullerene molecular acceptors was prepared and screened for sacrificial photocatalytic hydrogen evolution activity. PCDTBT/PC60BM nanohybrid showed a high hydrogen evolution rate of 105.2 mmol g-1 h-1 under visible light (λ > 420 nm)

Linear conjugated polymer photocatalysts with varied linker units for photocatalytic hydrogen evolution from water

Polymer photocatalysts have shown potential as for light-driven hydrogen evolution from water. Here we studied the relative importance of the linker type in two series of conjugated polymers based on dibenzo[b,d]thiophene sulfone and dimethyl-9H-fluorene. The alkenyl-linked polymers were found to be more active photocatalysts than its alkyl and alkyne-linked counterparts. The co-polymer of dibenzo[b,d]thiophene sulfone and 1,2-diphenylethene has a hydrogen evolution rate of 3334 µmol g-1 h-1 and an external quantum efficiency of 5.6% at 420 nm

Metal-organic conjugated microporous polymer containing a carbon dioxide reduction electrocatalyst

A metal-organic conjugated micorporous polymer (CMP) containing a manganese carbonyl electrocatalyst for CO2 reduction has been synthesised and electrochemically characterised. Incorporation in a rigid framework changes the behavior of the catalyst, preventing reductive dimerization. These initial studies demonstrate the feasibility of CMP electrodes that can provide both high local CO2 concentrations and well defined electrocatalytic sites

Hydrogen evolution from water using heteroatom substituted fluorene conjugated co-polymers

The photocatalytic performance of fluorene-type polymer photocatalysts for hydrogen production from water in the presence of a sacrificial hole scavenger is significantly improved by the incorporation of heteroatoms into the...</p

Mapping binary copolymer property space with neural networks

The extremely large number of unique polymer compositions that can be achieved through copolymerisation makes it an attractive strategy for tuning their optoelectronic properties. However, this same attribute also makes it challenging to explore the resulting property space and understand the range of properties that can be realised. In an effort to enable the rapid exploration of this space in the case of binary copolymers, we train a neural network using a tiered data generation strategy to accurately predict the optical and electronic properties of 350 000 binary copolymers that are, in principle, synthesizable from their dihalogen monomers via Yamamoto, or Suzuki-Miyaura and Stille coupling after one-step functionalisation. By extracting general features of this property space that would otherwise be obscured in smaller datasets, we identify simple models that effectively relate the properties of these copolymers to the homopolymers of their constituent monomers, and challenge common ideas behind copolymer design. We find that binary copolymerisation does not appear to allow access to regions of the optoelectronic property space that are not already sampled by the homopolymers, although it conceptually allows for more fine-grained property control. Using the large volume of data available, we test the hypothesis that copolymerisation of 'donor' and 'acceptor' monomers can result in copolymers with a lower optical gap than their related homopolymers. Overall, despite the prevalence of this concept in the literature, we observe that this phenomenon is relatively rare, and propose conditions that greatly enhance the likelihood of its experimental realisation. Finally, through a 'topographical' analysis of the co-polymer property space, we show how this large volume of data can be used to identify dominant monomers in specific regions of property space that may be amenable to a variety of applications, such as organic photovoltaics, light emitting diodes, and thermoelectrics

Photocatalytic hydrogen production performance of 1-D ZnO nanostructures : role of structural properties

Synthesis of zinc oxide (ZnO) nanowires (NWs) grown via vapor-liquid-solid (VLS) process using Gold (Au) as a catalyst metal on aluminum-doped zinc oxide (AZO) seed layer is reported in the present work. During the growth procedure, the nucleation process helps us to obtain ZnO nanowires with Au on the tip, confirming the VLS growth mechanism. Different morphologies were obtained after the variation in the growth parameters in the VLS process, and further, their role in the photocatalytic performance was studied. Changes in the structural properties of nanowires allowed us to modify the aspect ratio and surface area of the nanostructures. X-ray diffraction (XRD) showed that the principal orientation of the nanowires was (002) in the present case. Scanning electron microscopy (SEM) showed the structural properties of 1-D nanostructures (nanowires), and statistical analysis revealed that the average diameter in the present case was found to be varied from 57 to 85 nm. Scanning transmission electron microscopy (STEM) technique revealed the different elements present on the surface of ZnO NWs. Further, the compositional profile of nanostructures was cross-verified using Energy dispersive Spectroscopy (EDS). Photoluminescence (PL) and UV Visible studies were employed to study the optical properties of nanowires. UV–Vis measurements showed the role of different structural properties of nanowires on the absorption spectra, especially in the visible region. The ZnO nanowires were tested as photocatalysts for hydrogen production from water splitting reaction, and it was found in particular nanowires with random orientation with optimal diameter distribution show the stable and highest photocatalytic performance

Linear conjugated polymer photocatalysts with various linker units for photocatalytic hydrogen evolution from water

Polymer photocatalysts have shown potential for light-driven hydrogen evolution from water. Here we studied the relative importance of the linker type in two series of conjugated polymers based on dibenzo[b,d]thiophene sulfone and dimethyl-9H-fluorene. The alkenyl-linked polymers were found to be more active photocatalysts than their alkyl and alkyne-linked counterparts. The co-polymer of dibenzo[b,d]thiophene sulfone and 1,2-diphenylethene has a hydrogen evolution rate of 3334 μmol g−1 h−1 and an external quantum efficiency of 5.6% at 420 nm

The potential scarcity, or not, of polymeric overall water splitting photocatalysts

We perform a high-throughput virtual screening of a set of 3240 conjugated alternating binary co-polymers and homo-polymers, in which we predict their ability to drive sacrificial hydrogen evolution and overall water splitting when illuminated with visible light. We use the outcome of this screening to analyse how common the ability to drive either reaction is for conjugated polymers loaded with suitable co-catalysts, and to suggest promising (co-)monomers for polymeric overall water splitting catalysts

From StrathCEKO to StrathCAN : building a community of climate education ambassadors from the bottom up in a higher education institution

The paper offers a reflective account of the University of Strathclyde’s activity and experience of implementing its first Strathclyde Climate Education Kick-Off (or StrathCEKO) as the catalyst for the emergence of a bottom-up movement involving staff and students focused on scaling up curricular and extra-curricular Climate Education activities across the institution – and beyond. StrathCEKO initially focused on two separate, but highly complementary, ‘off-the-shelf’ workshop offerings, which together encouraged participants to take a collaborative, peer-to-peer, systems thinking approach to understanding the cause and effects of climate change (i.e. the problem) and discussing/evaluating the range of mitigations and implementation challenges (i.e. the solutions) required to “keep 1.5 alive” and secure a sustainable future for all. One of these workshop offerings, Climate Fresk, is a highly engaging, gamified workshop, where participants - working with a trained facilitator in groups of 8 congregating around a table – are issued with a steady stream of cards throughout the workshop, lasting 3.5 hours in total. Each card represents a key part of the earth’s climate system, including influences on it and the impacts of it. Here, participants are challenged to use these cards to create a ‘fresk’ or collage or, from a systems thinking perspective, form a causal-loop diagram. This culminates in providing participants with a system-level view of the earth climate system, its causes, effects and impacts; and in doing so, encourages a ‘systems thinking’ approach to enhance participants’ understanding of climate change and in particular highlights less mainstream knowledge and understanding around climate tipping points. Following the original StrathCEKO, there was a realisation that despite the scalable peer-to-peer, train-the-trainer (or facilitator) model that made this Climate Education ‘tool’ so attractive to resource limited institutions, it still required a core community, with a clear identity and purpose, to take institutional ownership of these workshops to effectively roll them out. Furthermore, it was understood that ‘membership’ of this community should be open to all staff and students. The main responsibility of ‘the community’ with regards to these workshops should be for members to take individual responsibility to identify opportunities within their classes, departments, networks, even local communities, where these workshops could be organised and run – as well as collective responsibility to support these workshops as and when required. In addition to this practical, logistical, delivery role it became apparent that there was a need, and also an opportunity, for this fledgling Climate Education community to fulfil a more co-creative role. This would see staff and students come together to use other off-the-shelf Climate Education offerings developed by third parties (e.g. NGOs, think tanks), and develop more Climate (and Sustainability) Educational workshops and activities that could be used – expeditiously - by staff and students to scale-up climate education inside and outside Strathclyde. This community now has an identify, as well as a clear remit – the Strathclyde Climate Ambassadors Network (SCAN). This paper will present the journey so far, including the challenges, curriculum successes, activities under construction, as well as its strategic vision for the future