Role(s) of adsorbed water in the surface chemistry of environmental interfaces

Abstract

The chemistry of environmental interfaces such as oxide and carbonate surfaces under ambient conditions of temperature and relative humidity is of great interest from many perspectives including heterogeneous atmospheric chemistry, heterogeneous catalysis, photocatalysis, sensor technology, corrosion science, and cultural heritage science. As discussed here, adsorbed water plays important roles in the reaction chemistry of oxide and carbonate surfaces with indoor and outdoor pollutant molecules including nitrogen oxides, sulfur dioxide, carbon dioxide, ozone and organic acids. Mechanisms of these reactions are just beginning to be unraveled and found to depend on the details of the reaction mechanism as well as the coverage of water on the surface. As discussed here, adsorbed water can: (i) alter reaction pathways and surface speciation relative to the dry surface; (ii) hydrolyze reactants, intermediates and products; (iii) enhance surface reactivity by providing a medium for ionic dissociation; (iv) inhibit surface reactivity by blocking sites; (v) solvate ions; (vi) enhance ion mobility on surfaces and (vii) alter the stability of surface adsorbed species. In this feature article, drawing on research that has been going on for over a decade on the reaction chemistry of oxide and carbonate surfaces under ambient conditions of temperature and relative humidity, a number of specific examples showing the multi-faceted roles of adsorbed water are presented.

Volta Potential Evolution of Intermetallics in Aluminum Alloy Microstructure Under Thin Aqueous Adlayers: A combined DFT and Experimental Study

“…The literature includes experimental and theoretical studies in diverse research areas such as heterogeneous catalysis (Refs. [1,2] are examples of recent publications), meteorology [3,4], geology [5,6], physical chemistry [7,8], solar energy conversion [9][10][11], pharmacy [12], atmospheric chemistry [13], electrochemistry [14,15], tribology [16,17], and corrosion science [18,19]. Advancements in experimental and computational techniques have resulted in considerable progress in our fundamental view of water-solid interactions, and the research field has been summarized in a few most comprehensive reviews [20][21][22].…”

Thin water films and magnesium hydroxide fiber growth

“…On oxide surfaces water adsorption occurs instantaneously when they get in contact with humidity. 6 The reactivity of the chlorinated MgO nanocube ensemble is attributed to the presence of water multilayers as a conned liquid solvent medium for ions (Fig. 6).…”

“…3,4 Resulting solids are metastable, highly dispersed and, as such, subject to their interface and the chemical composition of the surrounding gas or liquid phase. Under ambient conditions and in humid environments thin-lm water is ubiquitous 2,5,6 and nanomaterials become instantaneously covered by water lms with thicknesses ranging between one molecular layer to few nanometers. 7 While the water-mineral oxide chemistry has received much attention in earth and environmental science 6,8 as well as in surface and materials science 7,9-11 signicantly less attention has been paid to interfacial water in the eld of nanomaterials chemistry.…”

“…Under ambient conditions and in humid environments thin-lm water is ubiquitous 2,5,6 and nanomaterials become instantaneously covered by water lms with thicknesses ranging between one molecular layer to few nanometers. 7 While the water-mineral oxide chemistry has received much attention in earth and environmental science 6,8 as well as in surface and materials science 7,9-11 signicantly less attention has been paid to interfacial water in the eld of nanomaterials chemistry. This is surprising if one considers that thin water lms can serve as a reaction medium for the growth and assembly of oxide nanostructures.…”

Construction and Characterization of an Indoor Smog Chamber for the Measurement of the Optical and Physicochemical Properties of Aging Biomass Burning Aerosols Native to sub-Saharan Africa

“…What happens to smoke particles in the absence of light and increased relative humidity (RH) is not yet clear (Murphy et al, 2006) and dynamic influence of humidity on the evolution of smoke particles is not defined (Li et al, 2015). Humidity may also change the physiochemical properties of aerosol during aging (Rubasinghege and Grassian, 2013). Understanding daytime and nighttime aging under the high RH conditions that are typical in the tropics is clearly needed.…”