Zheng-Xiao Guo - Publications#
Major Recent Publications (*Corresponding Author):
1. Z Li, S Gadipelli, H Li, CA Howard, DJL Brett, PR Shearing, ZX Guo*, IP Parkin*, F Li*, Tuning the interlayer spacing of graphene laminate films for efficient pore utilization towards compact capacitive energy storage, Nature Energy 5, 2020, 160-168.
2. Y Wang, X Liu, X Han, R Godin, J Chen, W Zhou, C Jiang, JF Thompson, MK Bayazit, SA Shevlin, JR Durrant*, ZX Guo*, JW Tang*, Unique hole-accepting carbon-dots promoting selective carbon dioxide reduction 100% to methanol by pure water, Nature Communication 11, 2020, 2531(1-9).
3. J Xie, SA Shevlin, Q Ruan, SJA Moniz, Y Liu, X Liu, Y Li, CC Lau, ZX Guo*, JW Tang*, Efficient Visible Light-Driven Water Oxidation and Proton Reduction by an Ordered Covalent Triazine-Based Framework, Energy & Environmental Science 11, 2018,1617-1624.
4. G Chai, K Qiu, M Qiao, M Titirici, C Shang, ZX Guo*, Active Sites Engineering Leads to Exceptional ORR and OER Bifunctionality in P, N Co-Doped Graphene Frameworks, Energy & Environmental Science 10, 2017, 1186-1105.
5. S Gadipelli, T Zhao, SA Shevlin, ZX Guo*, Switching effective oxygen reduction and evolution performance by controlled graphitization of a cobalt-nitrogen-carbon framework system, Energy & Environmental Science 9, 2016, 1661-1667.
6. GL Chai, ZX Guo*, Highly Effective Sites and Selectivity of Nitrogen-Doped Graphene / CNT Catalysts for CO2 Electrochemical Reduction (Edge Article), Chemical Science 7, 2016, 1268-1275.
7. S Moniz, SA Shevlin, D Martin, ZX Guo, JW Tang*, “Visible-Light Driven Heterojunction Photocatalysts for Water Splitting–A Critical Review”, Energy & Environmental Science 8, 2015, 731-759.
8. G Srinivas, H Patel and ZX Guo*, “Ultrahigh Pore Volume drives up Amine Stability and Cyclic CO2 Capacity of a Solid Amine@Carbon sorbent”, Advanced Materials 27, 2015, 4902-4902.
9. G Srinivas and ZX Guo*, “Graphene-based materials: Synthesis and Gas Sorption, Storage and Separation”, Progress in Materials Science, 69, 2015, 1-60
10. X Han, HM Stewart, SA Shevlin, R Catlow and ZX Guo*, Strain and Orientation Modulated Bandgaps and Effective Masses of Phosphorene Nanoribbons, Nano Letters 14, 2014, 4607-4614.
Research Impact:
Xiao’s research is strategically targeted at critical fundamental materials structural issues and synthesis processes that underpin mechanistic understanding and technological advancement, particularly in clean energy storage, conversion and harvesting, involving low-dimensional, high-surface area and/or porous structures. He has strongly contributed to the discovery, atomic doping and structural modifications of molecules, clusters, covalent organic frameworks (COFs), metal organic frameworks (MOFs), 2D structures / graphene (G), metal/ceramic nanostructures, and structural alloys and composites. He has authored and co-authored around 300 high-quality journal publications and over 300 conference papers/presentations (> 100 Keynotes/Invited). His quality outputs have appeared in Nature Energy, Nature Communications, Energy & Environmental Sciences, Advanced (Energy/Functional) Materials, Phys. Rev. Lett., Nano Letters, Angewandte Chemie Inter Ed, Chemical Science, ACS Catalysis, ACS Nano, Energy Storage Materials, and invited reviews in Progress in Materials Science and Chem Soc Reviews.
In many cases, he led concerted efforts to explore the boundaries of properties in novel structures, e.g. the first discovery and in-silico engineering of exceptional tunable bandgaps and charge-carrier mobilities in semi-conductive oxides, COFs and 2D nanoribbons (P, Ge, GO etc) for potential applications in electronic-/photonic-devices [2,3,7,10]. These papers ignited extensive follow-up activities worldwide, which confirmed experimentally the predicted properties.
Very often, Xiao has been able to lead the combination of theory and experiment within his own research group, leading to cross-coupled theoretical predictions and experimental refinements, which result in well-integrated approaches to materials discovery. This approach, bringing in appropriate collaborators, pin points critical insights and progressively develops practical synthesis schemes to produce high-performance nanostructures with specific functionalities. Moreover, he is able to identify the common root of the challenges and channel such insight and understanding to practical development. In electrochemistry, he has focused on the critical issues of energy capacity, reversibility, stability and cost by carefully harnessing interlayer spacing, structure and chemistry of non-(noble)-metal catalysts, such as graphene-oxide (GO) and glassy graphene. His team identified clear active sites for oxygen catalysis, screened in-silico the potential configurations around such sites and derived practical means to enrich the materials with catalytic sites in the effective positions, leading to highly efficient catalysts for reversible oxygen catalysis in metal-air batteries and fuel cells [4-6], CO2 conversation and highly efficient supercapacitors and batteries [1,8,9].
Again driven by the challenges of clean energy supply, Xiao has led extensive development of hierarchical porous structures for selective sorption and storage of hydrogen, carbon dioxide and methane. His team discovered a facile heat-treatment and chemical grafting methodology to tune the chemical moiety, porosity and stability of “metal-organic-frameworks”(MOFs), leading to new records in CO2 uptake capacity, selectivity and temperature-swing window for sorption/desorption [8]. Similar approaches are being applied for the understanding and engineering of hydrogen conversion/storage/purification mechanisms and structures [>50 publications in main list]. These studies have led to considerable follow-up research activities worldwide and so are producing promising materials for safe solid-state storage and the clean generation of hydrogen, which is the ideal clean energy vector.
By adapting genomic-engineering approaches for the integration of experiment and multiscale modelling simulations, Xiao proposed an experimentally steered data-mining approach to accelerate effective research discovery, development and deployment. This foreshadowing of the now popular “Big Data” effort, was part of the 2002 initiation of the now established “International Conference on Multiscale Materials Modelling” in which Xiao launched with Profs Marshall Stoneham (FRS, RIP), Richard Catlow (FRS) and David Pettifor (FRS). Xiao has since built up a unique strength in implementing such approaches to successful effect, particularly in leading to clear understanding of fundamental interactions between solids and “energy molecules” such as H2, O2, CO and CO2. This has led to the development of cost-effective nanostructures and processes for hydrogen storage/purification [8,9], electrochemical catalysis [1,4-6], CO2 capture [9] and photoelectrochemical catalysis [2,3,7].
Extending his expertise in electronic structure simulations to guide experimental development, Xiao has fostered strong collaborative activities with experimental expertise in band-gap engineering and in electronic device engineering. This has led to discovery of heterojunction semiconductive structures [7, & >10 publications in full list], graphitic carbon nitride [3,10 etc.], and novel covalent triazine framework (CTF) -based polymer semiconductors [2,3 etc.] - with band-gaps matching the visible light spectrum and band-edges driving effective water splitting and CO2 / CH4 conversions. This offers not only insight for novel structural development but also significant potential impact on clean energy conversion using only renewable energy resources.
Xiao’s predictive work has been more often carried out with focused experimental study within his group and/or in collaboration, e.g. the the discovery of Te-based monolayer materials [PRL,2017,119,106101] and Pt nanocluster seeding mechanisms at MoS2 grain boundaries [ACS Nano, 2018,12,5626]. These novel materials are enriching the rapid development of 2D materials and structures. Such effort has been recently applied to generate electronic/photonic devices, such as highly selective and transparent MoS2/glassy-graphene photodetectors [Adv. Mat., 2018,30,1706561], where electronic structural simulations clarified coupling interactions and directed the synthesis of effective heterostructures.
Prof Guo’s earlier work on structural materials and composites was also based on innovative development and adaptation of different modelling approaches to identify important structural features and their roles in determining mechanical and other physical properties and hence material optimisation. Examples include the development of both strong and tough ceramic composites based on TiB2-TiC via facile reaction synthesis [> 10 publications in Acta Mater etc]. These composites have been practically applied as thermal protection barrier coatings that can withstand temperatures of a few thousand degrees. Xiao has developed a model for microstructural evolution, which predicts processing-microstructure-property relationships and facilitates the optimisation of manufacturing processes to generate the most desirable microstructures for targeted aerospace applications [20], which has been followed by many research groups.
Prof. Guo is exceptional in his additional skills in tackling practical challenges, through a very positive attitude in engaging with academic colleagues, industrialists and other stakeholders to generate cost-effective solutions. His team working has developed highly effective low-dimensional structures for energy molecular sorption/conversion and for effective photocatalysis, leading to highly cited articles, with one article named as one of the world top-10 highly cited in solar energy (DOI: 10.1002/anie.201403375). Within an international collaborative effort, the Xiao’s group developed an ultra-high energy density supercapacitor by matching between electrolyte ionic size and the graphene layer spacing of the electrode [1], a novel binder-free electrode material using highly conductive single-wall carbon nanotube film as a current collector and in-situ polymerised polyimide as electro-active material (Advanced Materials 10.1002/adma.201305452); and a flexible and efficient all-carbon yarn microsupercapacitors, via. wet-spinning of single-walled carbon nanotubes and chitosan composite into a yarn and then chitosan carbonization to form a composite yarn electrode containing SWNT and active carbon enriched with mesopores, leading to exceptional transport and storage of charges (Advanced Materials, 10.1002/adma.201400399).
Professor Guo has always emphasised the importance of fundamental scientific understanding of phenomena and processes, and their applications in advancing (energy) technologies. The fundamental insights of electronic structures, molecular binding and kinetic barriers have directly guided experimental design and discovery of effective sorbent structures, electrochemical catalysts and photocatalysts, and have optimised the synthesis routes for such structures. His impact includes two recent patents and invited review articles in “Chem. Soc. Reviews” (is one of the journal’s “Hot Paper of the Year”, and “Progress in Materials Science” (also named as a highly cited article).
All of the innovative findings have been timely disseminated, either within the academic community or with an extensive portfolio of industrial collaborators and supporters. Current work in several national and international research consortia means that Prof. Guo is actively engaged with E.On, Johnson Matthey, QinetiQ, E4Tech, Doosan Babcock, PQ Silica, Cambridge CMOS, Master Carbon and several SMEs. Since joining the University of Hong Kong, he has quickly built up programmes and research links in the region, while leading active bridging roles for UK/EU universities and organisations, including the recent success of a joint EU/HK Horizon 2020 / HKRGC project (SABYDOMA).
