Noble metal single-atom catalysts (SACs) can provide maximized interaction with the reactants and tunable electronic structure dictated by the coordinated support, thus enabling unprecedented high activity at a reduced noble metal cost. However, the practical utilization of SACs that enabled heterogeneous catalysis has the bottlenecks in high manufacturing cost, low catalytic efficiency, and low atomic utilization of metals due to poor porosity of supporting structures, low affinity between SACs and supports, and high-temperature synthesis involved. A scalable and low-energy consumption synthesis of SACs strongly coordinated with an atomically designed 3D nanostructure is needed to realize higher catalytic efficiency and atomic utilization efficiency. Here, a facile synthesis strategy is developed by applying low-cost cerous MOF (Ce-MOF) with tailored defects across the porous and crystalline structure. SACs (Pt) synthesized by cryogenic photoreduction can be enclosed at the defects in Ce-MOF. Due to the uniform dispersion and the unique electronic hybridization with Ce-MOF, the conjugated catalyst with a low weight content of 0.12 wt % exhibited 100% conversion of CO at a low temperature of 150 °C, consuming only 10% of Pt required by state-of-the-art catalysts operating under the same conditions, standing as the most effective catalyst reported to date.

The formation of ammonia (NH 3 ) as a byproduct during the operation of a three-way catalyst (TWC) in a simulated exhaust stream was investigated using a commercially available Pd/Rh TWC under steady-state and lean/rich cycling conditions. Ion molecular reaction-mass spectrometry was applied to determine NO, NO 2 , and NH 3 concentrations at a time resolution of 0.6 s. Catalyst aging was shown to result in a significant increase in the amount of NH 3 formed, which has received limited attention in the literature to date. The selectivity toward NH 3 formation has been shown to increase with the decrease in the oxygen storage capacity (OSC) of a TWC induced by thermal aging. NH 3 has been shown to mainly form within the exhaust temperature range of 250−550 °C. Typical lambda and rich operational condition duration periods found in vehicle test procedures were also employed to investigate their effects on NH 3 formation. The results suggest that a decrease in the lambda and/or an increase in the duration of rich operating conditions will lead to an increase in the selectivity toward NH 3 formation. Improving the OSC of TWCs and effectively controlling the lambda near to 1.0 with limited duration in rich operating conditions are therefore significant factors in the reduction of NH 3 emissions.

Increasingly demanding exhaust emissions regulations require that automotive three-way catalysts (TWC) must exhibit excellent catalytic activity and durability. Thus, developing TWC based on an accurate understanding of deactivation mechanisms is critical. This work briefly reviews thermally induced deactivation mechanisms, which are the major contributor to deactivation, and provides an overview of the common strategies for improving durability and preventing deactivation. It highlights the interaction of metals with supports and the diffusion inhibition of atoms and crystallites in both washcoats and metal nanoparticles and concludes with some recommendations for future research directions towards ever more challenging catalyst manufacture to meet increasing durability requirements both now and in the future.

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The synergy between active Pt species and ceria results in the presence of more coordinately unsaturated Pt2+ and Pt4+ species, which were found to be critical to drive C− and C−H bonds activation and enhance propane oxidation. Surface lattice oxygen on ceria in the vicinity of electron‐deficient Pt species provides the enhanced reactivity for low‐temperature propane oxidation. The reducibility and amount of activated surface oxygen species play a significant role in improving the reaction rates of propane oxidation in the 150∼300 °C temperature range. Ceria effectively promotes oxidative redispersion of platinum crystallites supported on alumina during propane oxidation in O2‐rich conditions, due to the unique ability to trap and stabilize ionic platinum.