The GAO Materials Chemistry Research Group

90% of our commodity chemicals and fuels are made from thermocatalysis industries driven by heat or grid power. In the context of carbon-neutral society, sunlight-driven photocatalysis is an ideal alternative to thermocatalysis especially for CO2 and H2O utilization. However, how to scale the lab-scale photocatalysis into real industry remains uncertain. To amplify, the efficiency of photocatalysis not only rely on the temperature related reaction rates but also the utilization of charge carriers, which requires simultaneous optimization of quantum yield and light transport. The challenges lie in photocatalyst and photoreactor engineering to use every incident photon reaching every catalytic site while minimizing parasitic absorption, reflection, scattering, transmission, and thermal conductive, convective, and radiative losses. See full story at Advanced Science News.

Professor Geoff Ozin has disseminated scientific knowledge in and beyond academe in remarkably creative ways. In addition to writing pioneering textbooks Cryochemistry, Nanochemistry and Concepts in Nanochemistry, he has written general-audience science books, including his most recent, The Story of CO2 : Big Ideas for a Small Molecule (which, in a featured interview in The Washington Post, US Energy Secretary Jennifer confirmed she was reading), with another to be published in the New Year with the Royal Society of Chemistry, 2022, Energy Materials Discovery for a Sustainable Future. He is also a constant presence in accessible science media, including the prestigious Wiley-VCH Advanced Science News– all part of his continuing leadership efforts.

Solar energy and CO2 utilizations are recognized as key to counter the global warming and build a “net-zero” sustainable society, and the surging global temperature has set the deadline of establishing revolutionary techniques in several decades. The urgency requires to assess most feasible current pathways among various solar energy and CO2 proposals and stick to it progressively. Athan Tountas, Prof. Ozin and Prof. Sain recently published their perspective ‘Solar methanol energy storage’ in the Nature Catalysis focus issue ‘CO2 Reimagined’ that acknowledges the five-year anniversary of the Paris Agreement. In it they explore the feasibility of storing renewable energy in the form of intermittent solar energy as methanol and highlight the performance and efficiency advantages of using CO-rich syngas derived from commercial-ready RWGS technology compared to direct-CO2 processes. The Focus is dedicated to progressing the fundamental science and practical implementation of this technology to advance climate goals.

With COP26 happening now in Glasgow, Scotland, there are still common concerns about where the money will come from to transition our economies to clean energy, the viability of carbon taxes, and how long the transition will take. By explaining the transition policy and estimating the technology development, Athan and coauthors suggest that new capacity in Canada will be funded by firms and investors and ultimately consumers, and establishing a steadily increasing carbon tax, improving solar, wind, batteries and other technologies are likely to take a few decades. See full story at Advanced Science News.

In a global effort to counter the energy crisis and meet the IPCC 1.5 C goal, photocatalysis and eletrocatalysis that can transform carbon dioxide into a myriad of value-added products such as fuels and feedstock chemicals, are regarded as promising solutions. In the upcoming International Symposium on Photo & electro Catalytic CO2 Reduction held by Naikai University (China), Geoff, together with 14 world top CO2 experts is invited to discuss on the state-of-the-arts, future opportunities and challenges on the emerging field.

Green hydrogen is promising to decarbonize the energy, transportation and industry sectors to counter the climate crisis. But the levelized cost of any form of green hydrogen must be competitive with steam methane reforming at $2.5/kg. Recently, a cheap yet powerful water splitting device has been assembled in Germany. In the device, a triple-junction thin-film a-Si:H/a-Si:H/μc-Si:H photovoltaic modules are directly coupled to an anion exchange membrane of an alkaline water electrolysis cell. A scale-up demonstration showed the solar-to-hydrogen efficiency exceeding 10% at a 10 m2 scale, and less than 10% activity decrease in a 9-month test. See full story at Advanced Science News.

Making solar chemicals and fuels enabled by photothermal CO2 catalysis is proving to be a promising pathway to counter climate change and the energy crisis. Advanced photothermal materials design can capture the merits of broad-band spectral absorption and high efficiency in CO2 photocatalysis. In a paper published in Nature Energy, researchers from the groups of Le He, Sochow University, and Geoffrey Ozin, University of Toronto, learned how to mimic the sunlight trapping effect of a conventional greenhouse at the nanoscale, to improve the photon conversion of methanation and reverse water gas shift reactions, with spectacular results. They synthesized a hybrid nickel nanocrystal sheathed by porous silica, the heat insulation and infrared shielding effects of which confine the photothermal energy and surface chemistry to the nickel core, while CO2-H2 reactants and CO-CH4 products enter and escape through the porous shell. In essence, a nanoscale greenhouse has been discovered which facilitates high efficiency CO2 supra-photothermal catalysis.

CO2 reduction to commodity chemicals and fuels holds great promise to alleviate the global warming. The realization typically requires earth-abundant catalysts and inexpensive driving force. In this paper, Jiuli and coauthors reported a Cu2+-substituted hydroxyapatite (Ca10(PO4)6(OH)2) mineral photocatalyst achieving peak CO2-to-CO performance of 215 μmol per gram catalyst per hour without CH4 byproduct. The activity originates from novel active sites of surface frustrated Lewis pairs—the proximal Lewis acidic Cu2+ and Lewis basic OH-, which selectively produce CO via a formate intermediate. See full story at Advanced Science.

Nitrous oxide (N2O) is a colorless gas that can make people laugh or feel pain relief, as well as a long-term agent to warm the planet and deplete the ozone layer. Specifically, its warming impact is 300 times more potent than CO2. Life cycle analysis indicates that most of the atmospheric nitrous oxide (75%) originates from agricultural soil management due to excess usage of nitrogen fertilizer. To confront the N2O crisis via a cost-effective way, Prof. Ozin proposes a photocatalysis pathway involving HNO3 + 2H2O + hv –> NH4OH + 2O2 in the first place. See full story at Advanced Science News.

We are honoured and delighted to announce that The Story of CO2: Big Ideas for a Small Molecule has launched its Chinese version published by Science China Press. It is a new landmark right after the bronze medal in Indie Book Prize. The translation is carried out by Prof. Wei Sun and Prof. Le He, two experts in CO2RR and distinguished alumni of Ozin’s group.