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A series of novel ZnO quantum dots modified with rare earth metals was successfully prepared by a simple sol-gel approach. The effects of types (Eu, Er, Tb, Yb, Ho, La) and amounts (from 0.09 to 0.45 mmol) of lanthanides on the optical properties, structural characterization and photocatalytic activity of ZnO/RE QDs were systematically investigated. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) with energy dispersive X-ray analysis (EDX) and UV–Vis diffuse reflectance spectroscopy were used to characterize surface properties, while photoluminescence (PL) emission spectroscopy and UV–Vis-driven degradation of phenol in aqueous phase were applied to understand optical and photocatalytic properties. The experiments demonstrated that generally modification of ZnO QDs by lanthanides resulted in increase of photoactivity while photoluminesce decrease at the same moment. The highest photocatalytic activity among all obtained nanomaterials and the lowest photoluminescence quantum yield among ZnO/Er photocatalysts were observed for ZnO QDs modified with 0.09 mmol of erbium. Increased photocatalytic activity has been shown in successive samples: ZnO/0.09_Er > ZnO/0.18_Eu > ZnO/0.09_La > ZnO/0.27_Er > ZnO/0.18_Tb > pristine ZnO QDs. The experimental results were supported by calculations based on density functional theory (DFT) which revealed atomic and electronic structure of Er/La modified ZnO QDs.

In this work, the effect of various ionic liquids (ILs), namely, choline chloride [Chol][Cl], hexadecylpyridynium chloride [HDPy][Cl], and tributylmethylammonium chloride [TBMA][Cl], on the morphology, surface composition in relation to photocatalytic oxidation of 5-fluorouracil (5-FU) and phenol in the presence of TiO2 photocatalysts under artificial sunlight conditions was investigated. The highest photoactivity towards cytostatic drug removal was found when [TBMA][Cl] was used for the synthesis, for phenol removal photoactivity was not changed in all cases. Among the selected ionic liquids, only [TMBA][Cl] made it possible to form the Ti3+ species, which was equivalent to the occurrence of oxygen vacancies and was beneficial for the photocatalytic activity. Moreover, the increase of ILs-TiO2 photoactivity was assigned to the presence of IL or IL’s organic residues on the photocatalyst surface responsible for better hole and electron separation. The mechanism of 5-FU degradation over the most photoactive photocatalyst was varied under different types of light irradiation, and •OHfree radicals were the major entities in the drug removal under UV light, while holes and •OHfree radicals under solar light. These studies represent a promising approach to cytostatic drug removal in the presence of TiO2 microspheres prepared in the presence of others than imidazolium-based ILs.

Novel mono- and bimetallic nanoparticles (MNPs and BNPs) decorated surface of perovskite-type KTaO3 photocatalysts were successfully synthesized by hydrothermal reaction of KTaO3 followed by photodeposition of MNPs/BNPs. The effect of noble metal type (MNPs = Au, Ag, Pt, Pd, Rh, Ru or BNPs = Au/Pt, Ag/Pd, Rh/Ru), amount of metal precursor (0.5, 1.0, 1.5 or 2.0 wt%) as well as photoreduction method (simultaneous (both) or subsequent (seq) deposition of two metals) on the physicochemical and photocatalytic properties of MNPs- and BNPs-KTaO3 have been investigated. All as-prepared photocatalysts were subsequently characterized by UV–Vis diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET) specific surface area and pore size distribution measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (PXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) emission spectroscopy. The crystal structure was performed using visualization for electronic and structural analysis (VESTA). The photocatalytic activity under Vis light irradiation was estimated in phenol degradation in aqueous phase and toluene removal in gas phase, while under UV–Vis light irradiation was measured amount of H2 generation from formic acid solution. The absorption properties of O2 and H2O molecules on KTaO3(1 0 0) surface supported by Au or Au/Pt NPs was also investigated using density-functional theory (DFT). The experimental results show that, both MNPs-KTaO3 and BNPs-KTaO3 exhibit greatly enhanced pollutant decomposition efficiency under Vis light irradiation and highly improved H2 production under UV–Vis light irradiation compared with pristine KTaO3. MNPs deposition on KTaO3 surface effects by disperse metal particle size ranging from 11 nm (Ru NPs) to 112 nm (Au NPs). Simultaneous addition of Au/Pt precursors results in formation of agglomerated larger metal nanoparticles (50–100 nm) on KTaO3 surface than subsequent deposition of Au/Pt with composition of concentrated smaller metal nanoparticles (>50 nm) on KTaO3 surface. The 0.5 Au/1.5 Pt-KTaO3_both and 2.0 Rh-KTaO3 reveal the highest Vis-induced activity among prepared samples in aqueous phase (14.75% of phenol decomposition after 90 min of irradiation) and gas phase (41.98% of toluene removal after 60 min of irradiation), respectively. The theoretical calculations confirmed that adsorption energy of O2 and H2O molecules was increased after loading of Au or Au/Pt NPs on KTaO3(1 0 0) surface. Control tests with scavengers show that O2 − radical is significantly involved in phenol oxidation under Vis light irradiation, which proposed mechanism is based on direct electron transfer from MNPs/BNPs to conduction band of KTaO3. The highest amount of H2 evaluation is obtained also by 0.5 Au/1.5 Pt-KTaO3_both after 240 min of UV–Vis light irradiation (76.53 µmol/min), which is eleven times higher than for pristine KTaO3 (6.69 µmol/min). Moreover, the most photocatalytic samples for each model reaction present good repeatability and stability after subsequent three cycles. Summarized, MNPs- and BNPs-KTaO3 are promising material in advanced applications of photocatalysis.

The step-by-step growth of yttrium oxide layer was controlled in situ using X-ray photoelectron spectroscopy (XPS). The O/Y atomic concentration (AC) ratio in the surface layer of finally oxidized Y substrate was found to be equal to 1.48. The as-grown yttrium oxide layers were then analyzed ex situ using combination of Auger electron spectroscopy (AES), elastic-peak electron spectroscopy (EPES) and scanning electron microscopy (SEM) in order to characterize their surface chemical composition, electron transport phenomena and surface morphology. Prior to EPES measurements, the Y oxide surface was pre-sputtered by 3 kV argon ions, and the resulting AES-derived composition was found to be Y0.383O0.465C0.152 (O/Y AC ratio of 1.21). The SEM images revealed different surface morphology of sample before and after Ar sputtering. The oxide precipitates were observed on the top of un-sputtered Y oxide layer, whereas the oxide growth at the Ar ion-sputtered surface proceeded along defects lines normal to the layer plane. The inelastic mean free path (IMFP) characterizing electron transport was evaluated as a function of energy in the range of 0.5–2 keV from the EPES method. Two reference materials (Ni and Au) were used in these measurements. Experimental IMFPs determined for the Y0.383O0.465C0.152 and Y2O3 surface compositions, λ, were uncorrected for surface excitations and approximated by the simple function λ = kEp at electron energies E between 500 eV and 2000 eV, where k and p were fitted parameters. These values were also compared with IMFPs resulting from the TPP–2 M predictive equation for both oxide compositions. The fitted functions were found to be reasonably consistent with the measured and predicted IMFPs. In both cases, the average value of the mean percentage deviation from the fits varied between 5% and 37%. The IMFPs measured for Y0.383O0.465C0.152 surface composition were found to be similar to the IMFPs for Y2O3.

A series of ZnMgO oxide films single doped with arsenic was grown by plasma assisted molecular beam epitaxy method. The concentration of Mg in Zn1-xMgxO alloys was evaluated on the basis of X-Ray photoelectron spectroscopy (XPS). Changes of the band gap energy in Zn1−xMgxO were evidenced by cathodoluminescence measurements. Analysis of high resolution As 3d XPS spectra revealed three arsenic states with binding energies of ∼41 eV, 44.2 eV and 45.6 eV assigned to: deep acceptor of AsO, acceptor AsZn-2VZn and donor AsZn, respectively. Small concentrations of AsO species were detected in all samples. The As contribution due to AsZn-2VZn centers was found to be intensive, and increased with the concentration of Mg.

A novel two-step ionic liquid assisted procedure was applied for a controllable synthesis of BiOBr/Bi2WO6 heterojunction thin films. The preparation route involved an anodic oxidation of tungsten foil and hydrothermal transformation of as-anodized oxide in the presence of bismuth precursor and ionic liquid, N-butylpyridinium bromide [BPy][Br]. The BiOBr plates with irregular shapes adhered to the surface of flower-like Bi2WO6 and formed a heterojunction between BiOBr and Bi2WO6, as confirmed by the analysis of their structure and composition. The highest efficiency of phenol degradation was achieved when the highest amount of IL was used (the apparent quantum efficiency was almost 8 and 71.5 times higher compared to BiOBr and Bi2WO6, respectively). In addition, superoxide radicals (•O2–) were found as the main factor responsible for the photodegradation. A possible reaction mechanism was further investigated as a function of monochromatic irradiation to determine the exact range of the composite photoactivity.

Si/Nb/Si trilayers formed with 9.5 and 1.3 nm thick niobium layer buried in amorphous silicon were prepared by magnetron sputtering and studied using XPS depth-profile techniques in order to investigate the change of Hall coefficient sign with thickness. The analysis of high-resolution (HR) XPS spectra revealed that the thicker layer sample has sharp top interface and metallic phase of niobium, thus holes dominate the transport. In contrast, the analysis indicates that the thinner layer sample has a Nb-rich mixed alloy formation at the top interface. The authors suggest that the main effect leading to a change of sign of the Hall coefficient for the thinner layer sample (which is negative contrary to the positive sign for the thicker layer sample) may be related to strong boundary scattering enhanced by the presence of silicon ions in the layer close to the interface/s. The depth-profile reconstruction was performed by SESSA software tool confirming that it can be reliably used for quantitative analysis/interpretation of experimental XPS data.

A novel synthesis process was used to prepare TiO 2 microspheres, TiO 2 P-25, SrTiO 3 and KTaO 3 decorated by CdTe QDs and/or Pt NPs. The effect of semiconductor matrix, presence of CdTe QDs and/or Pt NPs on the semiconductor surface as well as deposition technique of Pt NPs (photodeposition or radiolysis) on the photocatalytic activity were investigated. The as-prepared samples were characterized by X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) with energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), photoluminescence spectrometry (PL), Fourier transform infrared (FT-IR) and Raman spectra, diffuse reflectance spectroscopy (DRS) and BET surface area analysis. The photocatalytic decomposition of toluene in gas phase, activated by light-emitting diodes (LEDs), with the CdTe/Pt nanoparticles-modified TiO 2 microspheres, P25, SrTiO 3 and KTaO 3 semiconductors was investigated under UV–vis and visible irradiation.The results showed that the photoactivity depends on semiconductor matrix. The highest photoactivity under Vis light was observed for KTaO 3 /CdTe-Pt (R) sample (56% of toluene was decompose after 30 min of irradiation). The efficiency of the most active sample was 3 times higher than result for P25 and two times higher than for unmodified KTaO 3 .

Electron transport properties in praseodymium (Pr) foil samples were studied by elastic-peak electron spectroscopy (EPES). Prior to EPES measurements, the Pr sample surface was pre-sputtered by Ar ions with ion energy of 2–3 keV. After such treatment, the Pr sample still contained about 10 at.% of residual oxygen in the surface region, as detected by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) analyses. The inelastic mean free path (IMFP), characterizing electron transport within this region (4 nm-thick), was evaluated from EPES using both Ni and Au standards as a function of energy in the range of 0.5–2 keV. Experimental IMFPs, λ , were approximated by the simple function λ = kE p , where E is energy (in eV), and k = 0.1549 and p = 0.7047 were the fitted parameters. These values were compared with IMFPs for the praseodymium surface in which the presence of oxygen was tentatively neglected, and also with IMFPs resulting from the TPP-2M predictive equation for bulk praseodymium. We found that the measured IMFP values to be only slightly affected by neglect of oxygen in calculations. The fitted function applied here was consistent with the energy dependence of the EPES-measured IMFPs. Additionally, the measured IMFPs were found to be from 2% to 4.2% larger than the predicted IMFPs for praseodymium in the energy range of 500–1000 eV. For electron energies of 1500 eV and 2000 eV, there was an inverse correlation between these values, and then the resulting deviations of −0.4% and −2.7%, respectively, were calculated.

Most efforts in heterogeneous photocatalysis are focused on development of new and stable photoactive materials efficient in degradation of various pollutants under visible-light irradiation. In this regard, the wide-bandgap perovskite semiconductors, i.e., SrTiO3 (titanate), SrSnO3 (stannate) and AgTaO3 (tantalate), were prepared by a solvothermal method, and then modified with carbon quantum dots (CQDs) or graphene quantum dots (GQDs) co-modified with erbium. The photocactivity was investigated for: (i) toluene degradation (gas phase), (ii) phenol decomposition (aqueous phase), and (iii) inactivation of Escherichia coli K12 bacteria. It has been found that the morphology of semiconductors depends on the synthesis conditions, resulting in the formation of spherical particles, rods and faceted particles for SrTiO3, SnSrO3 and AgTaO3, respectively. Additionally, deposition of CQDs and GQDs/erbium has resulted in an enhancement of light harvesting, thus improved photoactivity under visible-light irradiation. Samples modified with both erbium and GQDs revealed much higher photoactivity than corresponding pristine and CQDs-modified samples. Moreover, all photocatalyst modified with GQDs and Er exhibited a significant antibacterial properties under visible light irradiation (λ > 420 nm). Accordingly, it has been proposed that obtained semiconductors modified with QDs and Er are promising candidates as sustainable, clean and cheap materials for environmental purification under solar radiation.

Bismuth tungstate (Bi2WO6) can work as a photocatalyst but suffers from rapid recombination of photogenerated charge carriers. Herein, density functional theory (DFT) simulations revealed that the formation of a thermodynamically stable AgInS2(112)/Bi2WO6(010) heterojunction could promote charge separation and enhance the photoactivity of Bi2WO6. To confirm these theoretical predictions, a new type of photocatalysts in the form of Bi2WO6 flower-like microspheres decorated with different amounts of AgInS2 quantum dots (QDs) was obtained using a three-step procedure. The optimized system, obtained by embedding 1 wt% AgInS2 QDs on a Bi2WO6 matrix, possessed an enhanced photocatalytic activity for both phenol degradation and water splitting under visible light irradiation (λ > 420 nm), as well as good reusability and stability during prolonged storage. Finally, DFT calculations of the adsorption energies of reagents (O2, H2O, and H2 molecules) on Bi2WO6 and AgInS2/Bi2WO6 surfaces showed that the surface of the AgInS2(112)/Bi2WO6(010) interface was more active, allowing this system to strongly interact with surrounding species such as H2, O2, and H2O and thereby inducing photocatalytic oxidation of OH– to •OH, reduction of O2 to O2•– or reduction of H+ to H2.

Electron transport properties in CeO2 powder samples were studied by elastic-peak electron spectroscopy (EPES). Prior to EPES measurements, the CeO2 sample surface was pre-sputtered by 0.5 keV Ar ion etching. As a result, an altered layer with thickness of 1.3 nm was created. X-ray photoelectron spectroscopy (XPS) analysis revealed two chemical states of cerium Ce4+ (68%) and Ce3+ (32%) at the surface region of CeO2 sample after such treatment. The inelastic mean free path (IMFP), characterizing electron transport, was evaluated as a function of energy within the 0.5–2 keV range. Experimental IMFPs were corrected for surface excitations and approximated by the simple function λ = kEp, where λ was the IMFP, E denoted the energy (in eV), and k = 0.207 and p = 0.6343 were the fitted parameters. The IMFPs measured here were compared with IMFPs resulting from the TPP-2M predictive equation for the measured composition of oxide surface. The measured IMFPs were found to be from 3.1% to 20.3% smaller than the IMFPs obtained from the predictive formula in the energy range of 0.5–2 keV. The EPES IMFP value at 500 eV was related to the altered layer of sputtered CeO2 samples.

TiO 2 modified with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles have been prepared using a water-in-oil microemulsion system (water/AOT/cyclohexane) followed by calcination step. The effect of metal ratio, reducing agent type (NaBH 4 or N 2 H 4 ), TiO 2 matrix type (P-25, ST-01, TiO-5, TiO 2 nanotubes or TiO 2 obtained by TIP hydrolysis) as well as calcination temperature (from 350 to 650 °C) were systematically investigated. Obtained photocatalysts were characterized by UV–vis diffuse-reflectance spectroscopy (DRS), BET surface area measurements, scanning transmission microscopy (STEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity under visible light ( λ > 420 nm) has been estimated in phenol degradation reaction in aqueous phase. The results showed that phenol degradation rate under visible light in the presence of TiO 2 loaded with Au/Pt nanoparticles differed from 0.7 to 2.2 μmol dm −3 min −1 for samples prepared using different reducing agent. Sodium borohydride (NaBH 4 ) favors formation of smaller Au/Pt nanoparticles and higher amount gold in Au/Pt is in the form of electronegative species (Au δ − ) resulted in higher photoactivity. TiO 2 obtained by TIP hydrolysis in microemulsion system seems to be the best support for Au/Pt nanoparticles from all among investigated matrix. It was also observed that enhancement of calcination temperature from 450 to 650 °C resulted in rapid drop of Au/Pt-TiO 2 photoactivity under visible light due to surface area shrinkage, crystal structure change and probably change in Au/Pt nanoparticles morphology.

Preparation of new rare earth metal-containing TiO 2 nanocomposites (Nd 3+ /Er 3+ , Nd 3+ /Eu 3+ , Eu 3+ /Ho 3+ -TiO 2 ) using sol–gel route and their photoactivity under visible and ultraviolet light is reported. The obtained photocatalysts were subsequently characterized by Brunauer–Emmett–Teller (BET) method, UV–vis diffuse-reflectance spectroscopy (DRS), luminescence spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction analysis (XRD). Photodegradation efficiency of phenol and acetic acid was estimated for visible light ( λ > 420 nm) and UV irradiation. It was found that introduced rare earth (RE) metals are presented in the form of metal oxides (RE 2 O 3 ) at TiO 2 surface. Our study demonstrated that Eu 3+ /Ho 3+ co-doped titania exhibited higher photocatalytic activity than P25 in phenol degradation under visible light, whereas Nd 3+ /Eu 3+ co-doped TiO 2 showed one of the highest activities in both phenol and acetic acid degradation reaction either under UV and visible light among all the rare earth doped samples. Action spectra analysis of the selected samples clearly showed that RE-doped TiO 2 could be excited under visible light in the range from 420 to 450 nm.

High-temperature induced transformations of the bulk structure as well as the surface and bulk morphology of thin polycrystalline iron films have been investigated using a combination of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The polycrystalline Fe films were evaporated onto a quartz substrate at 78 K under UHV conditions and then annealed in situ within a temperature range 330–1000 K. The morphology of both the surface and bulk Fe films have been observed ex situ after successive annealing steps of the Fe film using SEM and cross-sectional TEM analysis, respectively. An anisotropic polycrystalline bulk morphology accompanied by a fine-grained surface and the formation of microvoids was observed after heating the Fe film at 330 K. The iron films annealed at higher temperatures, exhibit large grain size surface morphology. Polycrystalline Fe film transformation occurred at an annealing temperature of 700–1000 K, resulting in the formation of a columnar microstructure of the bulk phase. The crystallites formed as a result of annealing at 1000 K revealed a monocrystalline structure characterised by low-index Fe bcc diffraction patterns.

A flow technique has been applied to measure the partial sticking probabilities of deuterium and nitrogen, simultaneously interacting with thin iron films at 78 K. The features of sticking probability dependence on the quantity of nitrogen and deuterium consumed have been analysed for both simultaneous and post-dosing D2 and N2 adsorption and then have been compared with the corresponding dependencies measured for D2 and N2 separately adsorbed on clean iron film. It was found that simultaneously dosed N2 and D2 adsorb on Fe film with high sticking probabilities (≤1) at low coverage. A part of co-adsorbed nitrogen admolecules is removed from the Fe surface due to competitive adsorption of deuterium at higher coverage. The population of nitrogen simultaneously adsorbed with deuterium on the Fe film surface is similar to that found for the D2 adsorption on Fe film pre-covered with strongly adsorbed nitrogen admolecules and much higher than the population obtained after the post-dosing N2 adsorption on Fe film pre-covered with deuterium adspecies.

Deuterium desorption from the surface of decomposing palladium deuteride was studied while monitoring the atomic component of the desorbing gas by means of an adsorption method. A thin gold film was applied as an adsorbent active for D adsorption, but inert against interaction with D2. The deuterium deposit thereby collected on the Au surface was analysed by means of thermal desorption mass spectrometry (TDMS). The atomic component of deuterium arising by desorption from decomposing PdDy was clearly detected. The experimental results obtained for PdDy are compared with those observed during the decomposition of PdHx, as well as the decomposition of other hydrides including TiHz and VHu.

Atomic hydrogen adsorption on thin copper films deposited under UHV conditions was examined by means of Thermal Desorption Mass Spectrometry (TDMS) and measurements of corresponding relative resistance changes ( ΔR R ). It was found that at 78 K, within a coverage interval 0.02 θ ΔR R with increasing θ. TD spectra showed a large TD peak with a temperature maximum T m at 300 K and traces of a very small TD peak (with θ on the order of 10 −4 ) at a T m of 170 K. At θ > 0.3 a weakly bound, inferred to be an induced form of the adsorbate was seen with a T m at 230 K. No traces of molecular hydrogen adsorption could be observed until the H 2 pressure, P , was below 0.1 Torr.

The interaction of hydrogen with methane-precovered thin palladium and platinum films at 298 K has been studied by means of surface-potential change (ΔSP) measurements and thermal desorption mass spectrometry (TDMS). It has been observed that adsorption of hydrogen on thin Pd and Pt films is complicated by interaction with preadsorbed methane adspecies. Most of the methane adsorbate is replaced by hydrogen but part of it remains on the surface affecting the electrical character of the hydrogen adsorbate on thin Pd and Pt film surfaces. The ΔSP measurements reveal the ability of thin Pd films precovered with strongly adsorbed methane and hydrogen adspecies at 298 K to form palladium hydride at 78 K. The TD spectra indicate the existence of a subsurface state of hydrogen on methane-precovered Pd film at 298 K. The origin of ΔSP due to hydrogen adsorption and reaction with preadsorbed methane adspecies on thin Pd and Pt films at 298 K is carefully analyzed.

The kinetics of hydrogen interaction with thin palladium films at 195, 298, 348 and 360 K was studied by means of surface-potential change (ΔSP) measurements and thermal desorption mass spectrometry (TDMS). Dissociative adsorption occurs at all temperatures, forming mobile states of the hydrogen adsorbate. The kinetics of adsorption at 298 K, at coverage θ ≥0.8, is strongly influenced by interaction within the adsorbate layer. Two TDMS peaks, well described by second-order desorption kinetics, were detected when hydrogen adsorption was carried out at 195 K. However, a small part of the hydrogen adsorbate desorbs according to the first-order kinetic equation. This effect can be attributed to the existence of interactions between adsorbed hydrogen atoms, subsurface hydrogen, or can be related to structural imperfections of the Pd film surface. A detailed analysis of the isothermal desorption of the weakly adsorbed hydrogen species was performed. The results obtained from TDMS and from isothermal desorption are compared.

Atomic hydrogen emission from the surface of thin palladium hydride films PdH x during their decomposition was studied using thin Au films as a selective adsorbent for H atoms from a desorbing (H + H 2 ) mixture. The influence upon this phenomenon of Pd films sintering and the population of weakly bound atomic hydrogen adspecies on a PdH x surface was examined.

The kinetics of hydrogen interaction with thin cobalt films at 78 K have been studied by means of sticking probability and surface potential changes (ΔSP) measurements and by thermal desorption mass spectrometry (TDMS). Hydrogen was found to adsorb with a high initial sticking coefficient ( S 0 close to unity). The mechanism of hydrogen incorporation into the bulk of Co film has been analyzed. Three TDMS peaks were detected. The TDMS peak arising from hydrogen adsorbed at equilibrium pressure > 1×10 −6 Torr was attributed to the desorption of hydrogen species incorporated into the bulk of Co film. A detailed analysis of the isothermal desorption of a weakly adsorbed hydrogen adspecies has been performed.

The nature of hydrogen adsorption on thin platinum films at 78, 195, 273 and 298 K has been studied by means of sticking probability measurements and thermal desorption mass spectrometry (TDMS). A high value of the initial sticking coefficient (S0 ≈ 0.95) was found at all temperatures. The behaviour of the sticking probability S as a function of hydrogen coverage θ has been analyzed. Three TDMS peaks of hydrogen were detected on Pt films when the adsorption was carried out at 195 K. The TDMS analysis carried out for hydrogen adsorbed at 78 K, revealed the existence of a molecular form of hydrogen deposit.

The kinetics and thermodynamics of hydrogen adsorption on thin cobalt films at 195, 273 and 298 K have been studied by means of sticking probability measurements, thermal desorption mass spectrometry (TDMS) and examination of adsorption isotherms. The dissociative adsorption occurs with a high initial sticking coefficient ( S 0 close to unity) at all temperatures. The behaviour of the sticking probability S as a function of hydrogen coverage θ has been analyzed. Two TDMS peaks were detected when hydrogen adsorption was carried out at 195 K. The isosteric heat of adsorption remains constant at 286 K up to θ ≈ 0.5 and then decreases indicating the arising of a new adsorbed state of hydrogen at θ > 0.5. A detailed analysis of the adsorption entropy for T ≈ 286 K has been performed.

It has been proved that hydrogen atoms desorb from the surface of a decomposing thin palladium hydride film. A thin gold film deposited and sintered in situ was used as a selective adsorbent for atomic hydrogen. The TDMS (thermal desorption mass spectrometry) technique was applied to detect the adsorption of hydrogen on gold and to determine the amount adsorbed.