Abstract
Palladium promotion and deposition on
monoclinic
zirconia are effective strategies to boost the performance of bulk In
2
O
3
in CO
2
-to-methanol and could unlock superior reactivity if well ...integrated into a single catalytic system. However, harnessing synergic effects of the individual components is crucial and very challenging as it requires precise control over their assembly. Herein, we present ternary Pd-In
2
O
3
-ZrO
2
catalysts prepared by flame spray pyrolysis (FSP) with remarkable methanol productivity and improved metal utilization, surpassing their binary counterparts. Unlike established impregnation and co-precipitation methods, FSP produces materials combining low-nuclearity palladium species associated with In
2
O
3
monolayers highly dispersed on the ZrO
2
carrier, whose surface partially transforms from a
tetragonal
into a
monoclinic-
like structure upon reaction. A pioneering protocol developed to quantify oxygen vacancies using in situ electron paramagnetic resonance spectroscopy reveals their enhanced generation because of this unique catalyst architecture, thereby rationalizing its high and sustained methanol productivity.
A plethora of metal promoters have been applied to enhance the performance of In2O3 in CO2 hydrogenation to methanol, a prospective energy carrier. However, the lack of systematic catalyst ...preparation and evaluation precludes a direct comparison of their speciation and promotional effects, and consequently, the design of an optimal system. Herein, flame spray pyrolysis (FSP) is employed as a standardized synthesis method to introduce nine metal promoters (0.5 wt.%) into In2O3. Methanol productivity generally increased on M‐In2O3 with selectivity following Pd ≈ Pt > Rh ≈ Ru ≈ Ir > Ni ≈ Co > Ag ≈ In2O3 > Au. In‐depth characterization, kinetic analyses, and theoretical calculations reveal a range of metal‐dependent speciation which dictate catalyst architecture and degree of promotion. Atomically‐dispersed promoters (Pd, Pt, Rh, Ru, and Ir) grant the highest improvement in performance, particularly Pd and Pt, which markedly promote hydrogen activation while hindering undesired CO formation. In contrast, metals in clustered (Ni and Co) and nanoparticle (Ag and Au) forms display moderate and no promotion, respectively. This study provides an atomic‐level understanding of In2O3 promotion based on a unified protocol, and highlights the potential of FSP to engineer complex catalytic systems toward more efficient energy transformations.
Flame spray pyrolysis is used as a standardized synthesis method to study promotional effects of nine transition metals in In2O3‐catalyzed CO2 hydrogenation to methanol. The nature of the promoter determines the catalyst architecture (single atoms, clusters, and nanoparticles) and corresponding reactivity, as examined by in‐depth characterization, kinetic analyses, and theoretical calculations.
Transition metal carbides have numerous applications and are known to excel in terms of hardness, thermal stability and conductivity. In particular, the Pt-like behavior of Mo and W carbides has led ...to the popularization of metal carbides in catalysis, ranging from electrochemically-driven reactions to thermal methane coupling. Herein, we show the active participation of carbidic carbon in the formation of C
2
products during methane coupling at high temperature that is associated with the dynamics of Mo and W carbides. A detailed mechanistic study reveals that the catalyst performance of these metal carbides can be traced back to its carbon diffusivity and exchange capability upon interaction with methane (gas phase carbon). A stable C
2
selectivity over time on stream for Mo carbide (Mo
2
C) can be rationalized by fast carbon diffusion dynamics, while W carbide (WC) shows loss of selectivity due to slow diffusion leading to surface carbon depletion. This finding showcases that the bulk carbidic carbon of the catalyst plays a crucial role and that the metal carbide is not only responsible for methyl radical formation. Overall, this study evidences the presence of a carbon equivalent to the Mars-Van Krevelen type mechanism for non-oxidative coupling of methane.
Direct methane coupling - one of the holy grails of industrial chemistry - was shown to involve carbon exchange between the metal carbide matrix and methane.
Flame Spray Pyrolysis
In article number 2103707, Núria López, Javier Pérez‐Ramírez and co‐workers apply flame spray pyrolysis as a standardized synthesis method to investigate promotional effects of ...nine transition metals in In2O3‐catalyzed CO2 hydrogenation to methanol, revealing that catalyst architecture (single atoms, clusters, and nanoparticles) and corresponding reactivity are dictated by the nature of the promoter.
Abstract
A plethora of metal promoters have been applied to enhance the performance of In
2
O
3
in CO
2
hydrogenation to methanol, a prospective energy carrier. However, the lack of systematic ...catalyst preparation and evaluation precludes a direct comparison of their speciation and promotional effects, and consequently, the design of an optimal system. Herein, flame spray pyrolysis (FSP) is employed as a standardized synthesis method to introduce nine metal promoters (0.5 wt.%) into In
2
O
3
. Methanol productivity generally increased on
M
‐In
2
O
3
with selectivity following Pd ≈ Pt > Rh ≈ Ru ≈ Ir > Ni ≈ Co > Ag ≈ In
2
O
3
> Au. In‐depth characterization, kinetic analyses, and theoretical calculations reveal a range of metal‐dependent speciation which dictate catalyst architecture and degree of promotion. Atomically‐dispersed promoters (Pd, Pt, Rh, Ru, and Ir) grant the highest improvement in performance, particularly Pd and Pt, which markedly promote hydrogen activation while hindering undesired CO formation. In contrast, metals in clustered (Ni and Co) and nanoparticle (Ag and Au) forms display moderate and no promotion, respectively. This study provides an atomic‐level understanding of In
2
O
3
promotion based on a unified protocol, and highlights the potential of FSP to engineer complex catalytic systems toward more efficient energy transformations.
To determine the prevalence and mortality of ICU patients with severe sepsis in Germany, with consideration of hospital size.
Prospective, observational, cross-sectional 1-day point-prevalence study.
...454 ICUs from a representative nationwide sample of 310 hospitals stratified by size. Data were collected via 1-day on-site audits by trained external study physicians. Visits were randomly distributed over 1 year (2003).
Inflammatory response of all ICU patients was assessed using the ACCP/SCCM consensus conference criteria. Patients with severe sepsis were followed up after 3 months for hospital mortality and length of ICU stay.
Main outcome measures were prevalence and mortality. A total of 3,877 patients were screened. Prevalence was 12.4% (95% CI, 10.9-13.8%) for sepsis and 11.0% (95% CI, 9.7-12.2%) for severe sepsis including septic shock. The ICU and hospital mortality of patients with severe sepsis was 48.4 and 55.2%, respectively, without significant differences between hospital size. Prevalence and mean length of ICU stay of patients with severe sepsis were significantly higher in larger hospitals and universities (</= 200 beds: 6% and 11.5 days, universities: 19% and 19.2 days, respectively).
The expected number of newly diagnosed cases with severe sepsis in Germany amounts to 76-110 per 100,000 adult inhabitants. To allow better comparison between countries, future epidemiological studies should use standardized study methodologies with respect to sepsis definitions, hospital size, and daily and monthly variability.
Germline mutations in the BRIP1 gene have been described as conferring a moderate risk for ovarian cancer (OC), while the role of BRIP1 in breast cancer (BC) pathogenesis remains controversial.
To ...assess the role of deleterious BRIP1 germline mutations in BC/OC predisposition, 6341 well-characterized index patients with BC, 706 index patients with OC, and 2189 geographically matched female controls were screened for loss-of-function (LoF) mutations and potentially damaging missense variants. All index patients met the inclusion criteria of the German Consortium for Hereditary Breast and Ovarian Cancer for germline testing and tested negative for pathogenic BRCA1/2 variants.
BRIP1 LoF mutations confer a high OC risk in familial index patients (odds ratio (OR) = 20.97, 95% confidence interval (CI) = 12.02-36.57, P < 0.0001) and in the subgroup of index patients with late-onset OC (OR = 29.91, 95% CI = 14.99-59.66, P < 0.0001). No significant association of BRIP1 LoF mutations with familial BC was observed (OR = 1.81 95% CI = 1.00-3.30, P = 0.0623). In the subgroup of familial BC index patients without a family history of OC there was also no apparent association (OR = 1.42, 95% CI = 0.70-2.90, P = 0.3030). In 1027 familial BC index patients with a family history of OC, the BRIP1 mutation prevalence was significantly higher than that observed in controls (OR = 3.59, 95% CI = 1.43-9.01; P = 0.0168). Based on the negative association between BRIP1 LoF mutations and familial BC in the absence of an OC family history, we conclude that the elevated mutation prevalence in the latter cohort was driven by the occurrence of OC in these families. Compared with controls, predicted damaging rare missense variants were significantly more prevalent in OC (P = 0.0014) but not in BC (P = 0.0693) patients.
To avoid ambiguous results, studies aimed at assessing the impact of candidate predisposition gene mutations on BC risk might differentiate between BC index patients with an OC family history and those without. In familial cases, we suggest that BRIP1 is a high-risk gene for late-onset OC but not a BC predisposition gene, though minor effects cannot be excluded.
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