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In heterogeneous catalysis, hydrides on the surface or in the bulk play a critical role as either active components or reaction intermediates in many hydrogen‐involving reactions, but characterization of the nature and structure of these hydride species remains challenging. Neutron scattering, which is extremely sensitive to light elements, such as hydrogen, has shown great potential in meeting this challenge. In this Minireview, recent advances in neutron studies of hydride species, mainly over the two most typical classes of catalysts—metals and oxides—are surveyed. Findings on catalysts outside these categories are raised if they are considered to be relevant for contextualization in the present Minireview. The adsorption, dissociation, spillover, and reactivity of hydrogen, especially hydride species over supported metal and oxide catalysts, have been successfully investigated, mostly by means of neutron vibrational spectroscopy. Insights from these neutron studies, which are otherwise not possible with other techniques, shed light on the interaction mechanism of hydrogen with solid surfaces and reaction mechanisms in which hydrogen is involved. Future research challenges on neutron scattering studies of hydrides, as well as catalysis in general, are also highlighted, and more operando‐type neutron studies need be conducted to advance the field. Suitable surfaces: In heterogeneous catalysis, hydrides play a critical role in many hydrogen‐involving reactions. Neutron scattering has the unique potential to characterize hydrides. Herein, recent advances in neutron studies of hydride species over supported metal and oxide catalysts are reviewed. [ABSTRACT FROM AUTHOR]

The gas-phase pyrolysis of proline, glucose, 1-[(2′-carboxy)pyrrolidinyl]-1-deoxy-d-fructose (the proline Amadori compound), and a 1:1 mixture by weight of proline and glucose was investigated at high temperatures (600–840 °C) and short residence time (i.e. 1.0 s) in an inert atmosphere to determine if glucose or Maillard reaction products enhance the formation of nitrogen containing polycyclic aromatic compounds (N-PACs) and polycyclic aromatic hydrocarbons (PAHs) in the pyrolysis of proline. To study the gas-phase formation of N-PACs and PAHs, the substrates were sublimed into the pyrolysis furnace at 460 °C. Thermogravimetric analysis showed that glucose, the proline/glucose mixture, and the proline Amadori compound undergo solid-state decomposition reactions before subliming. Thus, the substrates were pyrolyzed in two stages: at 460 °C during the sublimation and at 600–840 °C. At 800 °C with a residence time of 1.0 s, proline produced low yields of N-PACs, such as quinoline, isoquinoline, indole, acridine, and carbazole, and PAHs, such as phenanthrene, pyrene, benz[a]anthracene, benzofluoranthene isomers, and benzo[a]pyrene. Increasing the temperature and residence time increased the yield of these products. Under similar pyrolysis conditions, the proline Amadori compound produced 2–8 fold more N-PACs and PAHs than proline. A 1:1 mixture of proline and glucose produced a similar slate of pyrolysis products as the proline Amadori compound, but it is unclear whether the proline Amadori compound was an intermediate in the reaction. In general, the proline Amadori compound produced a higher yield of N-PACs and PAHs than the proline/glucose mixture, but glucose clearly enhances the low temperature gas-phase formation of N-PACs and PAHs from the pyrolysis of proline. For example, a 1:1 mixture of proline and glucose was found to produce low yields of quinoline, isoquinoline, and indole at 600 °C while proline alone does not produce these compounds until 800 °C. Thus, glucose provides a low temperature pathway for the decomposition of proline, which leads to formation of N-PACs and PAHs. [Copyright &y& Elsevier]